I just picked up an unmarked (973) Hamilton with a sn under 80,000. I never see much about these. Are they uncommon? It looks to me like the beauty of the movement is along the 990/991 lines. Comments?

Nice one Mike!That may be a detent stem movement, I see an arrow mark by the crown wheel.I imagine that one would be kind of scarce.What does it have for a dial?

Since you asked, the dial needs to come off and soaked and the movement cleaned up. Also has no crystal but I should have one in Oregon.

Pretty nice case as well

Nice watch Mike. It appears to be all original except maybe for the crown. It has a detent stem, and you should find it's 4 footed dial when you take it off.