[Arran]

Not exactly, the B has nothing to do with the cabinet finish, but it has everything to do with it being a 1954 model. Beginning in 1954 Philco abandoned it's practice of using the last two numbers of the year as a prefix for the model number, though I have no idea why. So U.S built Philcos built between 1937 and 1953 began with 37-116, 38-116, 39-116, 40-180, 42-327 etc. etc., but for 1954 they switched to using letters to denote the model year, which was something General Electric did in the 1930s and 40s.
For some strange reason they started with the letter "B" rather then an "A", I guess maybe it was to avoid confusion with car radio models where the "A" stood for auto. So if you have a Philco with a B-XXXX it's a 1954 model, if it's a C-XXXX it's a 1955 model. I don't really know what they planned to do when they ran out of letters, maybe double them up?
Regards
Arran