Newbie here but I am pretty sharp with the BMX market and prices, especially Schwinn BMX. I can give you a value but not sure if it is against the rules to post values openly in a thread? I will say the last pair of these I saw sell was a year or so back and they sold after sitting for sale a few months. Pretty cool tire, Schwinn's version of the "snake belly" tread from around 1978-82ish. These did not come as a stock tire but could be purchased at your local Schwinn dealer. The Stock tire on Scramblers was the BX "suction cup" knobby.
Other snake belly tires can sell for a lot if they are made by Cycle Pro or NTTK. Also, more money for gum-wall or skin-wall versions.
Only problem with these, being 1 3/4" I.D. and only fit the S-2 Schwinn rims. If you have a 70's or early 80's scrambler w S-2's these would work nicely. All in all, a pretty nice pick up! Hope that helps you out.
What are your plans for the tires?