Ruger Korean War Era Pistols with Tapered Bolt Ears

[BarkeyVA]

I have a Ruger T678 (1953) with Flat on top and a Ruger RST-4 (1953) with the Flat on the bottom. I'd like to know which configuration is more common.

[outta_ammo]

According to a drawing on page 33 of Hiddleson's Encyclopedia of Ruger Semi-Automatic Rimfire Pistols 1949-1992 "each variety appears at random on all of the .22 pistol models offered at this time."
So it doesn't appear that one was a more prevalent than the other.

[Watertender]

I have a feeling that the bolts were machined after they were put together. that would account for the random nature of the flat being in either direction. Not sure if any of the original 1950's vintage 2-piece bolts have ever come apart but my buddy Leon had the bolt on his KMK4 stainless Mark 2 end up in 2 pieces.