O.k., I see what you quoted in that post #10 there. However I also looked at a different post from Hans and he didn't disagree what West said there, see Post #2 and #3 here:
http://www.letstalkguild.com/ltg/showthread.php?156268-D15m-has-a-plywood-back
Hence I assumed that was correct what West said for most Guild laminated backs.
Wild. (And thanks for going along in the same spirit with my "search for the truth" )
Absent explanation from Hans, I'd have to conclude that in his usual fashion, he was narrowly addressing a specific model and build period, even though Jim said "
All the arched back models" which Hans clearly contradicted in the post I cited, and which Chaz seems to contradict in that same thread with his posts about his F50r (which granted is a highly unusual case, being very limited production in that arched back form and even "experimental" at the time).
As well, that thread shows lots of incidences of folks having negative connotations associated with the term "plywood", which is addressed by Killdeer in post #19, plywood and laminated are the same thing, but to most people "plywood" means "cheap low quality wood"
Also, your search Fu is magnificent as usual and I heartily recommend that thread because it is one of the best explorations of Guild's laminating methods even if some of those questions remain unresolved to this day, or at least in that thread.
I also want to point out that since that thread I've become much better educated about the principles of
back function, it
is primarily reflective and whatever's in the
center layer(s) of a laminate is irrelevant.
Here's another picture of the press, but that does not look to me like a 60ies machine.
Ralf
I can see that the control panel looks like later tech (the "LED" numeric displays), but that numeric display "look" was available in the early '70s' and the control panel could be upgraded in any case.
Not that it proves my point, I just think the only way to know for sure is to get a manufacturer's name and model from it if possible.
Form another perspective, the real point is that Guild was producing laminated pressed backs from day one, regardless of what the specific machine they used was.
The actual press looks old enough to my eyes, but I'm no expert.
Edit: Note that "Industrial Turquoise" color was also so generic in the '60's that even Heathkit used it:
