Lyman Reciever Sights Question

I have 2 Lyman reciver sights with no bases. I would say they are from 50s or earlier. The "shaft"
on both sights measure the same and have same dovetail angle. They both have Lyman trade mark but no model number. One sight has a stud on back of shaft than elevation screw goes into.
The other has no stud and elevation screw has the nut that set screw in base secures. I'm thinking
the studded one has to be a 57 or older similar model. Would the other be a 66? I want to get bases for these they are both in good shape. For what they want for a base I don't want to buy the wrong ones. Any experts on these?

Post pics - it will make the issue much clearer.