I think the price has dropped considerably on the original Series 70. I picked up a Colt Series 70 (1st Ed.) last month for $400 in a pawn shop. It had some cosmetic problems (some minor rust pitting) but after refinishing and rebluing, and replacing some small parts + Kings sights, it is a very good carry piece/shooter for $450 or so total.
While you might pay a premium for a LNIB older Series 70, I don't think that a used gun should command a premium over the new issue. I would rather have the new issue, all things being equal.
The same thing happened to the Winchester Pre-64 Model 70 prices, when they reintroduced the "new" Pre-64 style rifle. Priced dropped.
I am impressed with Colt's effort to produce a top quality product. People will pay for it. I am looking forward to getting a Combat Commander/S70 if they come out again.