I think the guitar we're talking about is the one from the video below, Ralf. Just checking. Right? I believe this is a bit of a mystery because of the following reasons:
#1) It is ba braced flat-back, not an arch-back like the 1967 F-412 SPEC that has been suggested;
#2) The fretboard inlays are incorrect for an F-412 SPEC.
#3) It's very hard to tell from a video of a relatively small man like JD, but it looks bigger than the 17" jumbos.
It's possible there were flat-backed F-412 SPECs; I don't know; I've never heard of them. It's also possible JD had those inlays done himself, but they look like the special inlays that Carlo Greco did for the F-612 -- and '69/'70 inlays we've seen on some F-512s -- but the bridge is a cloud without the stars I expect.
I also have heard some conjecture that JD played an F-212XL before he played the F-612. I doubt that too, as this guitar looks like rosewood to me.
I think this guitar is an F-612, Ralf, before the specs were clear (ornate headstork, herringbone trim, etc.).
[edit: Oh, I forgot to mention one other thing... This is apocryphal, but worth mentioning. The history of my old archie F-50R was that Dave Van Ronk had one of the same guitars. That was from the mouth of first owner (Capquest) who had visited Hoboken at the time it was built. There was never any mention of John Denver with that back of archies, and I would've suspected (again, apocryphal) that that would've been pretty relevant news.]
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