Show your wheels

I hope they work out for you. Please keep us posted. It appears that they are way out of production so be careful. As you probably know, tires do weaken/fail with age. They could be fine but generally speaking, tires are done at the ~10 year mark regardless of wear. Just a rule of thumb. The manufacture date should be on there somewhere...I'm going to guess that they're more than ten years old.
I'm very familiar with DOT dates. I checked the dates on them when I unwrapped them and they were only a few months old. Working for Harley we never sold and mounted tires older than 5 years old. We would sell them but not mount them. I worked for 4 different dealerships (2 in Nevada, 1 in Az. and 1 in NJ and that was their policy.