If the shells are brass, they are either Key Imports, Overland, or custom. Key and OMI are the only 2 importers to do BRASS F units (to my knowledge). Overland had a separate trim ring at the end of the headlight, the Key nose is all one piece. The Keys I have seen had small (streamlined) number boards, so once again guessing: OMI.
Pretty sure the A and B were BOTH powered as imported.
P&D Hobby shop has nice brass Blombergs and you could power both units as they were originally.
Simon