Ya know...  I looked at the first two pictures of the slide numbers, and immediately thought fake!  In addition to the fact that the scaling and numbers are different, it just looked totally wonky!  Seeing the side views just seals it for me!  As Whig said, who created this fake?  Obviously, someone is trying to cash in on the scarcity of the actual 1896 Carbine sight!

I don't know who made the sight. The previous owner kept good records of his purchases. This carbine was bought in 1998. I do not know if he added the sight himself or it came with the carbine. These knock offs might have been around for quite awhile. Something to watch for in the future. Thanks for the side by side comparison.

It's entirely possible that he was in need of a sight and unknowingly purchased a faked sight from someone else.  Based on what you've told us, it's likely that you were not misled intentionally... however, they previous owner may have been duped... or just didn't know what to look for.

Maybe there was never "Fakery" involved.

Somebody with knowledge and talent may have just wanted and made a credible 'Replica' copy of a model 1898 carbine.

We don't know. Intentions and the story have been lost, due to death. Possibly, everything was known and above board and no one was taken advantage of.

If 'King carp' feels like he made a bad mistake and was wronged, I'll give him $360 for his "Fake Carbine". 

There are lessons here for all of us:

1. We can easily contaminate history.

When we 'part together', repair, and restore a nice Krag, (or other gun), for our pleasure, 'Shooting', and use, the story of 'what we did' will be lost. Our handiwork may become an enigma and a cause of confusion to others.

Our present intentions are good and known. However, if our 'project' Krag passes into the hands of the unscrupulous, someone possibly will get 'screwed' in the future.

2. The regulars on the KCA Forum are nice guys, encourage and learn from each other.
However, our sharing of insights and information can be viewed and exploited by scoundrels and poltroons to fake and cheat "more better". 

We have to 'Dance' carefully.

I have seen forums before where very knowledgable collectors will withhold certain important facts regarding the authenticity determination for certain parts because they don't want to reveal that important determining factor to potential counterfeiters. This can be very frustrating for the honest ones of us who really want to know for honest reasons.  Most of these people will reveal information privately, though, which does help. As Butlers said, counterfeiters can read through many of our posts here and know exactly what we look at to determine faked parts. Their skills evidently improve with time and experience!

Many of us have also made repairs to our Krags to try to restore them, in a legit fashion, to a more functional or historically correct condition. When we do that, we try to never allow it to be advertised, sold or misrepresented as "authentic" or "original" but repaired. I have done that myself, with the help of many here,  and it makes the collecting of Krags all the more fun.

Sometimes, the Krag item, that doesn't look right and appears bogus, proves to be correct and a rarity.
Studying a 'well done fake' is a good learning experience.
The exchange of observations, insights, and knowledge advances understanding - IMHO

I personally enjoy the 'Krag Puzzles' that show-up on the KCA Forum. It's a fun way to learn and a way to stay mentally sharp. A growing pool of vigilant and knowledgeable observers turns up more stuff and helps broaden understanding.

'Faking' has always been a human endeavor.
IMHO - The only good defenses are better knowledge (than the faker), healthy skepticism, trained eyes, and openness to continued study and learning.