[Arran]

The set looks like it's in better shape then it did in the fleabay aution, which is good for you I guess. That bottom rail where the controls are definately looks like it has stump/burl walnut veneer applied to to it, the grain is still there and the finish is flaking off with the grain. I don't know how Philco Tropics were marketed but Philco should have tried selling them domestically, I know that they sort of did in Canada but not under the tropic name. I don't know how my 40-780 Tropic came to be here, I don't think that they were marketed in Canada. There seems to have been a greater interest in the Canadian market for sets with multiple shortwave bands, often many low and medium priced sets have three or more bands.
I wasn't even aware that it had a back, but given that it's an AC/DC set I guess it would have had one. Do you have another back to use as a pattern? There is this type of black cardboard material that is very similar to the cardboard they used for radio backs, it's used for automotive door panels in the auto trimming (upholstery) trades. An upholstery supplier should have it.
Regards
Arran