original '66 GT350H distributor

That's a hipo the date will tell you if it could be one used on a Hertz car. Of course you will need to compare it to when your car was at San Jose to be really correct. Don't want to install a dist that was made after your car was built

Quote from axelviejo

Would a distributor stamped (FOMOCO) C50F 12217 E be original equipment on a '66 GT350H(auto)?

I am guessing that your number includes a typo. I think the HiPo distributor should be:

C5OF 12127 E

with FoMoCo

Wasn't going to bring it up but you are very correct. Those stampings are not always very clear after all these years