I think that if you cannot match the caps to the third members you would be dollars ahead to junk the ones you have, sell them at a swapmeet some people will buy anything!
You "hit the nail on the head", Rex. As careful as I am, I'm still "some people".
I have
carefully been "collecting" 9" third members for a few years on EBay. Man, what a minefield EBay is! Everything, has a story. Its hard to tell when its outright deceit or just naivety. 99.99% of the time the seller leaves out pertinent information from the description. I always ask pertinent questions before bidding but I still have received bad parts. Most are honest sellers and have either paid for return shipping or just told me to junk them and returned my costs. The couple of 3rd members that are the reason for this thread are when it was just too much trouble or expense to go after the seller. One time I called the police dept in a small town in Wisconson about 12 miles away from the sellers home town. His town was so small they have no local law enforcement. When I mentioned the name of the seller the Chief said "what did Joe do now!" It was hopeless, I just dropped the issue.
Completely agree with you all. Lesson learned: With the cost of new stuff out there now, buying a "pig in a poke" is ridiculous. Thanks for identifying the machining that is involved it helped me make a decision.