I have heard that some of the originals did not have a part # on the back of one of the spokes. Is this true ?
Yes this is true. I believe that the ones with out the numbers are the second version that is supposed to clear ( from experience some will, some won't ) the 68 & up single piston K/H calipers.
Rodney
The naked set (no casting id) that I have I bought in the early 70s from Jeff Burgy. He had been using them a few years on his '66 GT350. They do not have the cast in spacer in them.
He actually had GR50-15 BFG's on that car with these wheels.
When I asked, he didn't remember where he bought them but thought they were local out of the Detroit area.
There are 15" 10 spokes listed in one of the Shelby accessory catalogs dated 1966. I'd speculate that they are before production use on '67 Shelbys. That started sometime around June of '67 when they became the "Deluxe" wheels.
My 67 GT500 is in a DSO group that had them installed new.