I'd go ahead and make up the faux BoOF for fun, if you want to. There will be enough "wrong" with it that no one would be fooled in a future sale. You can actually have the best of both worlds by keeping the sporter stock, as well, to use for hunting.

Whatever you do to the front sight will work just as well as the abortion that was on there, so you are really not losing anything.

Not to beat a dead horse but…..I cleaned the barrel with #9 and went over it very lightly with 0000 steel wool, and took a few more pic's.  I don't see the remnants of a notched flat on the barrel for a front sight.  chalk line is for reference.  Hopefully I can get an '03 sight to cover what looks like a hacksaw mark without having it  down the barrel too far.

Thank you to everyone for their comments and suggestions. 
Per Dick's suggestion I am thinking of making the faux BoOF.  Where else am I going to get a 26" barrel, and a good ballpark s/n.  But I can't use the existing stock for anything except to keep the action from being damaged.  I am a left handed-shooter.  Watch for it coming to an eBay auction near you, unless someone wants to jump to the head of the line on this beauty and make me an offer…………….anyone?….oh Well!

I've got a barrel with some of those pin slots, and noted that at one time various outfits were threading what they referred to as ordnance barrels, for the Krags.  I'm assuming they were machine gun barrels, for the most part.  Maybe BAR barrels too.  As long as it was .30 cal, it was probably fair game.

MPF, you did a very good job in cleaning off that solder and leaving the bluing. I would not have thought it could be done.
It does look like at least 2 different people did the work on your Krag. The person that did the soldering could not have been the person that did the fitting and carving on the stock.
I have read an old gunsmithing book were the author describes how to get the style of crown you have with hand tools and I know I could do it. The crown you have was blued after the work was finished. In your photos it almost looks like there are remnants of the factory sight underneath the bluing. If you will be covering up the saw cut anyway looking under the bluing for ButlersRanger's  brazing will not hurt anything.
I still could see this going either way, a nicely done hand finished crown or the SA conversion that was covered up.

Added Info. I just looked at my grandfather's old original 98 and the bluing covers the brazing. It was done so well I had always thought the barrel and sight were one piece. There is a very slight difference in the bluing on the brazing, now that I know what to look for.