Yours looks like it is missing the crown. That's a big problem because I broke the stem on this one some months ago and haven't been able to find a replacement anywhere.
It's a complex assembly which winds, sets, turns the inner bezel and when pushed, changes the date. It also has an o-ring, tiny spring, gear, etc.
Intact the watch is worth in the high hundreds. But I suppose you could spend that on restoration too, if you can find the parts. (If you do, PM me!)
BTW this watch was bought new in Mexico about 1971-72
Cheers,
Cazalea
This message has been edited by cazalea on 2016-08-08 16:57:41