Well, well, well - you, out of all the 2xxxxx and 3xxxxx wannabes, might actually have one! It DOES happen - just doesn't happen often!

133725, 133735, 133791, and 133919 are listed as genuine M1898 Carbines. Yours is close enough that it certainly cannot simply be dismissed out-of-hand, and the stock, which goes with no aother arm is one of the hard parts to find.

It should look EXACTLY like mine. The Model 1896C rear sight IS correct. Krag sights often show very little rhyme or reason as to what year model is on what arm.