Thank you bvillercr, the weights of your car at least give me an idea of what the tires have held speed and weight wise.
The "recommended" weight for each tire is listed on the Goodyear site. Goodyear manufacturers the Land Speed tires in "batches". They estimate each year what the need might be and produce a limited amount only. Usually there are enough tires to meet demand. However, in the past certain part numbers may have been out of stock and would not be replaced until the next year. That is the source of the "hard to find" rumor you hear frequently. The LSR tires are sold only through their racing dealers like Shelby, Summit, Roger Kraus. Because of the very low demand, dealers almost always order from a Warehouse Distributor. However, I did find a set of tires that were canceled by a customer and were in stock with Roger Kraus one year.