In my years of collecting vintage TV's I only ever sold one, but with money getting tighter I'm now considering selling a couple of my prize pieces. They are two early GE Portacolor sets, one from 1966 (the first year of production) and the other from around 1968. The older one has VHF tuning only, making it an especially unique display piece - I once saw one in a Hellmanns mayonnaise commercial. Both sets work great, or did when I last had them running a few years ago.
What I'm wondering is, just what are Portacolors worth these days? I saw a much later one on Ebay several years ago (went for about $250), but haven't seen any more since. Are they really that scarce, or do people just not bother listing them?
Here are pictures of my two sets:

I would only consider selling these if I was sure I could get a good price.
Thanks for any advice.