Lol, they always had the 12 on it, even before the KR55 came out. Art Decalb has a really nice copy of the original decal. His supply is limited if he has any left. I think the paint may not have been the same on all of them, as the depression hit, supplies dwindled and who needs to paint aluminum silver anyway. Mines pretty worn but even the gear foot shows some sign of paint.

The changes over the years were, carb and cylinder mainly. The displacement never changed. Some internal changes, rods went from bronze to aluminum. Too many things to lot here. The later ones, from KA39 and up were really the same internally. The KS has rope start, KD was deluxe and had recoil. Yes, they all use the prop was for cooling. The A, KA, was added when they changed the lower unit. Props are opposite turning on A and non a older versions.
See the photos page for a picture of my 1930 K-50 pushing my Thomson 16’ boat, also a 1930. Hope this helps.

I’ll have to measure my tiller. The K50 is shorter than the later versions so it may be correct. Just need the right rubber grip. Yes, the wood is an upgrade. Lol
Looking good on the bench. I notice your crankcase have the oil line to the top bearing, good. Some of the early ones, mine, did not have it. No idea why, the boss for it is cast in just never drilled out.