Most of the Fifty Fathoms Milspec are only Milspec, but there are some special ones, such as the Double Swiss, OR... The Rotomatic Incabloc.
Here are some photos I could take of one, belonging to a friend of mine.
An ultra rare version, as I could see only two in the real life, and a couple more on photos.
Yes, my friends, building a collection of vintage Fifty Fathoms is an impossible mission. You have to avoid the bad ones, and when you find a correct one, you just realize that there are several highly tempting versions.