For quite some time, I thought there was just basically one kind
of G&H single lever sidemount with just variations in the markings.
The first being marked "PAT. APPL. FOR" like this one

Griffin Howe early

Then later with a patent date,

patent date


But recently I saw one with a different locking mechanism, I don't have a picture of it, but it looks like this partial one

later variation?

So, naturally, I wonder how many variations there are now, and the relative rarities.