The first model 1902 sight had a 'leaf', like the model 1898 sight, but, fine serrations were machined on the left-side of the leaf. The slide 'locking-knob' was initially 'unslotted', but, eventually had a slot added, so that a cartridge rim could be used to tighten it. (The base of the 1902 sight is taller and has a different spring and curvature, than the model 1898 sight).

The next variant of the model 1902 sight had the leaf serrations changed to coarse serrations. Leaf graduations remained the same.

Eventually, a swing-up plate with a 'peep' was added to many, (but not all), of the 1902 sights.

(FWIW - I have seen drawings of another 'leaf' variation in manuals and a photo in Mallory's, "The Krag Rifle Story". This 1902 leaf has 'graduation lines' that do not go through, but, stop at the edge of the sight numbers.
I don't have one. I cannot recall, if I have ever really seen one. They are another interesting variant).

IIRC - The 1902 sight variation, that uses an altered 1898 leaf and eye-piece, was likely introduced, as a cost saving measure.

A final variation of the 1902 sight used the leaf, slide-locking knob, and eye-piece from early 1903 Rod-Bayonet Springfield sights. This leaf, (approved April, 1904), had fine 25 yard increments between the numbered graduations. On the left-side of the leaf was a fine 'cross-hatching' The 'locking-knob' had been slotted and 'dished', so that the rimless .30-03 cartridge could be used to tighten or loosen the knob.

These 1903 sight parts, (for a sight discontinued in 1905), were workable on the 1902 Krag sight.

The parts seem to have been used by Springfield and/or arsenals to rebuild or repair damaged Krag sights, up to the end of WW1. Lots of model 1902 sights have the 1903 knob and leaf. They are 'correct'.

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