I have another car with a BLACK VINYL interior I had converted to 134a. It worked fine for 2+ seasons. If you park it in the sun without AC, I do not know if you can cook eggs on the seats, but you can surely toast the buns. It leaks from a 40 year old diaphragm in an important AC part. The part is obsolete, and only Vintage Air makes an update. But no one with a evacuation pump and certification wants to mess with it. The word "Aftermarket" scares them, even if the part is off a newer model. I do not want burnt legs, so the car is not getting many miles when I should be driving it. If I had an old fridge I wanted to strip the pump from, as per certain directions on this site, it would be up and going.
My point - If you want an older car, you might have to fix it yourself a lot at first. Until it is restored it will be often, and then you still have to keep it up. And you have to wonder what the previous owners were thinking too. Hopefully it is worth avoiding new car payments to you. Once they outlaw all non electric cars, crush the rest, and acid rain from the electric plants destroys all the vintage sheet metal, we will not have to worry.