My apologies, those pics were too large to really see. My bad.  I will now leave you all alone.

Mark Sam:  The marks on your stock are an inspector's "cartouche" with the Inspector's initials and year of acceptance (probably J.S.A. = J.S. Adams).  The Circle stamp has a stylized 'P' in it for "passed".  Your stock is valuable because it is early and unaltered (ram rod groove not filled and 'flat butt plate').  The "pins or shim" are the remains of an early style magazine cut-off.  Don't mess with the finish of this Krag.  It is an early one and untrained efforts will destroy its value.  Get some Krag Books, at least Joe Poyer's, "The American Krag Rifle and Carbine".  You can get this for less than $20.  Early Krag Rifle Rear sight and Early style cut-off come up on eBay for not too much money.  Go slow!  You've had it for 40 years.  Don't ruin it now.

I truly appreciate the responses I've received re: my Grandfathers Krag.  It is fun to learn about it.  I've killed many deer/elk and a couple of moose but all with modern rifles.  Now, as I've grown older this old gun that I've held and wondered about for since I was a young boy seems compelling to me.  I want to clean it up and go kill a deer or elk in memory of my Grand-dad.  So thanks. I will follow your advice and buy a book ortwo and study up. Any other info for a "greenie" will be appreciated.  Re: cleaning it up, I'm not going to "refinish or re-blue" it as several have suggested.  I did receive this bit of info about the process, my question for you folks is this the way to get the paint off? and clean in up?  as follows:get a jar of Birchwood Casey  "Tru oil", which is a stock finishing oil that can be found at any of the bigger sporting good stores. I'd then get some 1500 and 1000 grit automotive sand paper (from Napa or Autozone) and gently wet sand the paint spots on the wood with the Tru oil and start with the 1500 grit. With some gentle wet polishing, the paint should soften and come off, and the Tru oil shouldn't change the color of the wood much. On the metal, I'd use a soft cloth and solvent like acetone or lacquer thinner and gently rub the wetted cloth until the paint spots come off. I wouldn't use the sand paper on the metal because it will polish off the patina and leave bright spots on the metal, which won't look good.

A bit longer answer.  Regards rifles, and skipping oddities, there are three models of Krag rifles.  Models, and rough numbers made, are as follows:
1892.  24,000
1896.  70,000
1898.  400,000.

As can be seen the 1892s are the least made.  Compounding their smaller numbers is the fact that over 20,000 were altered to 1896 format.  The rifles which missed that alteration are somewhat scarce.  That is what you have.

So, to the good, it's an unaltered 1892.
To the bad, it's been modified.
To the good, it can be restored.
To the bad, it's in weak shape.

Roller coaster ride isn't it?  Think "1966 Ford Mustang Shelby which somebody added wheel flairs and a sunroof too."  The basic rifle remains but it has some issues.

The gun is restorable.  Given the scarcity of that model many collectors would love to have it to restore.  Lots of Krag collectors will never get the chance to own an unaltered 1892 so the chance to restore one is appealing.

Yet you mention "sand paper" and other really awful items in regards that gun.  No attempt to "clean it up" will do it any good at all.  Modern restorations, in all things to include guns and cars, is "minimal restoration."  The days when the items were ripped down to the basics and put back together (over restored) are over.

So I can appreciate the family connection to the gun and it's a good thing.  Keep the gun.  I can also understand wanting to hunt with it.  So do so.  What gets my hair to stand up is the desire to "clean it up."  Ask a coin dealer if you should polish a coin and you'll get the same reaction: DEAR LORD NO!

Make sense?

You have a treasure twice over.  An unaltered 1892 and a family gun.  Keep it.  Appreciate it.  Don't muck with it.

Mark Sam:  I don't know how much you know about guns and proper dis-assembly & re-assembly.  Do you know how to remove the Bolt from a Krag?  Do you have proper fitting gunsmithing screwdrivers?  From your photos it appears there may be some cracks or splits in the wrist area of your Krag's gun stock (handle with caution).  Arm yourself with knowledge before you bugger everything up.  If you can remove the bolt, clean the barrel from the breech with a one piece stainless steel cleaning rod of adequate length.  Cleaning rod tip should be brass and for .30 cal.  Use .30 cal. bronze brushes and Hoppe's #9 solvent and flannel patches.  If you can take your rifle apart, do so and separate metal parts from wood.  I would clean the Metal parts of surface rust and hardened grease, paint and grime (lightly) by hand with #000 steel wool saturated with Hoppe's.  I would wipe paint spots on wood with old cotton 'T' shirt rags damped with Turpentine or Mineral Spirits (starting with a small trial area in the barrel channel).  I would wipe down larger areas of the stock with a 50/50 mix of Linseed Oil & Turpentine.  I'd finish up by hand rubbing the stock with Linseed Oil.  I might also try Pledge spay furniture polish.  I would use nothing more abrasive on wood than cotton rags or my thumbnail.

1892 sight

From the previous picture post you have a damaged magazine cut-off and a incorrect '96 rear sight. The correct and serviceable cut-off should look like the one posted above, not like the shaft only one you have depicted in IMG 0015 and 9952 of the previous post. Additionally, your rear sight does not appear to have step graduation on it like the one above, rather, the ladder ramp is smooth all the way like a '96 version.
Your rare old beast can indeed be restored with a handful of parts to a version that were mainly updated through arsenal upgrade. An arsenal upgrade is still a desirable weapon if original, the fact that most were upgraded makes yours very rare indeed and worthy of the cost of proper original parts. Just my observations, others on this site are far more knowledgeable than I.