[Ron Ramirez]

The 38-12CB did not have a back originally.

There were several Philco models that used this cabinet:

Brown Bakelite: 38-12CB, 38-14CB, 38-15CB, 39-3A1ACB, 39-3A5ACB, TH-3, 40-90CB, 40-710T, 40-2710T, PT-30, 41-705T
Ivory Plaskon (or painted Bakelite): 38-12CBI, 38-14CBI, 38-15CBI, 39-3A1ACBI, 39-3A5ACBI

Of those, I think only the PT-30, 40-710T, 40-2710T and 41-705T had backs originally. I cannot be sure about the Tropic models (40-710/2710 and 41-705) as I have never seen one, but am assuming so since it appears that most Tropic models originally had backs.

But I digress.

The PT-30 did have standoffs which attached to the back, and in turn were attached to the chassis. The cabinet has no provisions for fastening a back onto it.