I bought a full used tail light set with wiring attached and made the sure it had the four pin connector to the rest of the harness. The one in my car was cut. I'm going to use the existing connectors and tail light housings and replace the wiring with same colors/gauge.
It kind of stinks because there are pigtails and housings for front park lights, etc. for the more popular years. When I recently got my 73, I thought I'd done a lot of research to see what parts were available. But the car was completely apart and was abandoned before it was put back together. So many parts are not available/reproduced and "next time" I'll try to start with something more complete! But, the search is a lot of the fun.