Did you dig around the garage / basement for the pump where this car came from?

Before going too far with the water pump, bore scope the cylinders and look for rust. ( pull the valve cover too ) If no rust is found, use thin oil / diesel fuel to soak the cylinders for a hew hours then try to turn the engine by hand.

I'd then be doing a leak down and compression test. If this looks good, build a plate to block the water pump hole and attach any coolant hoses in order for the system to hold coolant. Remove the thermostat, fill with water then run the engine. You could even lightly drive it up and down the street in order to assess the car.

If the engine and trans check out, then it is worth installing a water pump. I'd expect this engine to be $$$ to rebuild so if it is bad / car is driver quality, consider a 4 cylinder and trans from a Ford Ranger / Chevy S10 / Early Dakota / 05 - 06 era Jeep Liberty - Wrangler 2.4 < the 2.4 in rear drive configuration is difficult to find.