Is this factory 1975 stuff

Once again more crap to make an otherwise okay day, completely crap out. I'm starting to hate this car. I'm trying to get the car into satisfactory running shape, for a trip to the body shop. There two rubber plugs in the firewall are confusing. I've never seen these on other cars. The grey wire is oil, the violet, and black are temp, green wire to the blower motor, there's a big red with a fusible link. going to the starter relay, etc, etc... But there's a dark blue wire that stops just by the blower motor with a female connector, nothing is plugged into it, and I'm wondering if that is the air conditioning.