there are several LTGers who own a D20. I have heard nothing but good news about the model.
I have heard that when Oxnard first got going, they were working thru some build issues, training staff, etc. Not many New Hartford employees went to Oxnard, and Ren was only involved in the very beginning of the move etc before he retired.
so i would not be surprised if there was some B-stock output to start, and the first acoustics they would have started with were the M20 and the D20. so maybe that guy got one of the early ones.
flatback D25s (D20) are not that easy to find, as they were only made from 1968-'71/'72 or so, though they did have a resurrection in either Corona or Tacoma, I forget. Al will know for sure...
I would keep an eye out on reverb for older D25s, like from that '68-'72 timeline. Those are really sweet. and before the '73/'74 when they got an arched back but still all hog, before the complete transformation to spruce topped, arched hog b/s.
still, i am pretty biased towards the Westerly acoustic Guilds. which is ok cause I grew up in RI. Guild acoustics are great across all eras of Guild location.