[Jacknola]

Gentlemen, thanks for your input. the sheath usually takes a back seat to the knife for collectors. In my case however, the narrow focus of my interest, US Vietnam era, causes me to be a bit more discriminating about the total package.

I readily agree that overlap in characteristics can and did take place. I'm not sure when the change to only stamped length for model 1&5 sheaths occurred. We do know it occurred because most or all model 1s in the 50s and 60s had two numbers, and most or all model 1s from the mid 70s forward had only one number. But that leaves a fairly substantial gap from (in my opinion) about 1970 to late 72-early 73. And I suppose it is possible that some sheaths were stamped with a single number earlier though I continue to be bit skeptical.

I am open seeing documented knives that help to pin this changeover date down. I have pictures of 3-4 model 1 sheaths with both numbers that are late 60s. The problem is... many cool old model 1s have been posted on the net, but few show the back of the sheath. And a great many beautiful old model 1s (and 5s) are now in newer sheaths because sheaths often don't last 50 years, unlike knives.

Perhaps I'll get motivated and collect info and submit it to the board for comment. This is not a big deal with me.

Regards,
Jack