[Arran]

RCA probably built the chassis in this case, however that was not unique as RCA also built some of the pre war U.S Westinghouse sets. I've never owned a house set under the Delco name, only car radios, and I am pretty certain that the car radios were built by Delco, or at least G.M themselves. I did see at least one Delco radio that a guy had for sale and it did have 1940s era RCA style round knobs, I don't remember if it was a U.S model or not, and quite frankly it was not of interest to me other then the brand name, which was not enough for it to overcome the rather dull and uninspired wooden cabinet it was housed in. It would seem that the more interesting looking Delcos came in Bakelite cabinets from what I have seen in books and in online photo galleries, but as to whom made the chassis I can't say as they rarely show pictures of the inside of any set.
Regards
Arran