I have a question for the experts. I could swear I saw references to Model 15 revolvers in the past that lettered as USAF shipped, but lacking the USAF or US markings. But I cannot find anything in my notes and references, so I might be misremembering or confusing with some other military S&W. Has anybody seen this in a confirmed factory letter? Also, I see the USAF contracts ran into 1969. Is that a hard date, or were any shipped at the tail end in 1970? TIA guys!