I'm not sure what pressure the folks were running on those tires, last ones i saw run was in the late 90's. I could ask if anyone remembers.
But I do have a very "BIG WARNING" DO NOT AIR THEM UP UNLESS THEY ARE FULLY MOUNTED ON THE HUBS!!!! The bolts that hold the rim halves together have been known to fail and could cause catastrophic injury or worse. Just saying.
Rouse