Restore factory ac or go aftermarket

Most aftermarket a/c system kits are designed for those vehicles that didn't get factory a/c. The kit may not install so easy in your car. Having said that... Your pre 73 factory push button climate controller was/is prone to failures. I don't know of 1 application where a mechanical type writer like switch block wasn't a trouble maker.
But hell, everything breaks eventually. At least we do have aftermarket support that lets us renew and maintain what we might be stuck with.