Definitely RCA, one thing makes me think it might be newer than 1956 though is it seems to be a slim set with no CRT cup, it looks like it's pushed right up against the wall, unless that's an illusion, or there was a hole in the wall?
This is a 1957 model and it has a long neck CRT, otherwise it looks like the same chassis and controls, I think they went to a slim 110 deg tube the next year.
