I still have my Spotmatic II from 1971. However, I took most of my Vietnam snaps with a cheap Kodak Instamatic since I didn’t want to risk the Pentax. Since I flew helicopters this meant those photos were wide-angle with more distance. Still works and at the time only the Nikon SLR was considered better (and cost a whole lot more).
Postscript: as a 54-year old reservist I got deployed in 2003 to Uzbekistan. I had the old Pentax sent to me from home and got some great shots of Central Asia. The young people, both Uzbek and American, were amazed at its heft and durability.
Takes a lickin’ and keeps on clickin’