Chuck,
If you were to sell it though I'd put an opening bid a little lower than that too accelerate the bidding.
The last Model 5, I knew of being sold just slipped out of my hands because the seller became confused. My telephone offer had been higher than that of the buyer, but the buyer showed up in person wasting no time with a big wad of bills and waved them in the seller's face. This is a good technique that often works! Three 15" RCA receivers described as CT-100's went on ebay about 3 years back from a retired RCA employee in New Jersey area. One turned out to be a Model 5. The 3 sets went for either $500 each or $1000 each in the lot as I recall. It wasn't any more than that. I've got it written down in my files along with the buyer's contact info. I remember speaking with the buyer. I recall learning that the Model 5 was making a raster for the buyer.
Under clear auction conditions with no behind the scene dealings and no economic depression I'd venture that a good condition Model 5 ought to easily command upwards of $10K.
Rob