I repaired a 15" RCA New Vista Color portable for astronaut Buzz Aldrin. That was in the 80s. I also worked on a cheap RCA (Hitachi) VCR for President Reagan when he had his office in Century City after leaving the White House. It was fun meeting & talking with Buzz, but I never got to meet Pres. Reagan... Never in the office
As far as Elvis, I've seen programs showing inside the Graceland mansion, and I recall seeing a row of CTC-25-ish metal RCA sets mounted in the wall in a theatre room...
Charles