Great guesses, I think the Elmar guesses came the closest, with Summar possibly close. I've never used a Summar but have looked at a lot of photos on screen.
It's an Industar I-22 50/3.5 collapsible screw mount on a Leitz screw to M adapter on the RD1. Glass is clear of haze and fungus, and no cleaning marks, but some dust, probably could use a clean.
I have to admit that on a few (maybe several) of the real out of focus ones, that is not a designed in focus shift of the lens like the Sonnar, it was me not pulling the tube out completely.
The conversion from JPG/film mode 1 color from the RD1s to Sepia mode was done in Picasa.