Here are two wrist shots of my very vintage G-P as promised. Note domed crystal. To gauge the size, the strap is 19mm at the lugs. Further delay unfortunately because I will have to search for the book entry and scan the page for tomorrow UK time as I am away from home. PeterCDE wrote a few years ago on here an interesting long article about the calibre 86 G-P movement and its comparison with the Mimo FE86.
There is a number 936944 inside the case back and the movement has the reference 86 4213. The movement seems to have been imported and cased in USA.
Best
Clive