You are likely to have gasket issues, as you said, which means leaks at the every jet and suction, as well as unions and pumps. And let's not forget valves. Shaft seals are probably bad too. Motors might be siezed up. Heater is almost certainly bad. Pressure switch is definitely bad. If it has a blower, that's going to scream like a banshee, if it runs at all.
The controls might still work, but I wouldn't count on it. Relays that haven't fired in 10 years tend to stick.
Used spa rule #1: See it running.