Mystery bulb socket behind dash

Sorry, but a 50+ year old car. A factory manual and schematics are a must. If they look like a Chinese scroll, trade the car for a rickshaw.
The guy I bought the harness from said it was a 71. From what I’ve been able to tell through all the wiring diagrams I’ve printed, he was right. But to me those diagrams are like trying to read an ancient Chinese scroll lol