Hey, fellow CTC121 owner! Mine is actually a JC Penney 685-2501J (which had a dark oak cabinet) which now resides in a medium oak RCA cabinet. If it didn't have a rear cover that says JCP it would pass for an RCA. It has the full A/V jack pack. I used to work on VCR/TV's in the '90's and got this for free in '91. It had 3 different problems, both audio and video, when I got it which kept me busy but that beautiful oak cabinet is what kept me pushing on.
I have what I believe to be the RCA version of the original remote that I bought new in '91. I don't remember which 121 it is but if I remember right it has a letter suffix that was only used for JCP models. Sometimes there weren't a lot of differences between the letter suffixes and other times there were. When servicing you really need to know which model you're working on, otherwise there are 'surprises'. Like an IDIOT, lost the service data I had for it. I had it 'customized' for the version of the chassis it is and was all annotated with all the repairs I've made over the years. RATS! Anyway, after it's last repair about 5 years ago it keeps on chuggin and, I dare say, has the same gorgeous picture it probably had new in '84 (unlike other sets I've had that turned 'green')! Although the amp is stereo, the tuner is not so this is a good canidate for a convertor box- maybe I can get another 20 years out of her. Enjoy yours as I have with mine!
Brian