So here is what I know.
The original owner was Pete Sayers, a country singer from UK who went to Nashville in the mid 60s. Whether he bought it in the UK and took it to USA, or whether he bought it there is not clear. There is a rumour that he bought it from an established US performer after he arrived. Pete was involved in a morning radio show in Nashville, and met loads of "names". There is a video of Mel Tillis playing a D50 with a similar wear pattern to mine from I think 1969. Pete played the Guild at the Opry, and featured briefly as a hobo playing the guitar in a Lassie movie. He returned permanently to the UK in the early 70s, but by then he had got a Martin which he preferred. I do have a picture of Pete playing it at the Cambridge Folk Festival in the late 60's/early 70s. He sold it to a guy who took it with him on VSO (Voluntary Service Overseas) to Kenya for a couple of years. I bought it from him in 1974 for £100, including an original Paxman case. It has had a refret, and leveling of the fingerboard. There was a side hole where a pickup output jack had been installed, which was professionally filled at the same time. I had an undersaddle pickup installed in the 80s. Otherwise I think it is pretty original, and still plays and sounds like a dream. I mainly use it at home now - she is an old lady who needs to be treasured.