Nice score! Congrats.
Drain the gas tank and clear all the lines. I would run it off a gas can first, then do the tank later.
Drain/refill oil, rebuild carb and clear out the sediment.
Me- I would make sure the oil looks good, throw a battery in it, then see if it turns over. If it does, let it crank for 10-15 seconds to get some oil moving, make sure it has oil pressure. Then, dump some gas down the carb, ounce or so and see if it fires up. If it runs at all then you know the ignition works. This will also tell if they are lying and the motor is blown or it has a spun bearing, thus making all maintenance a waste of time. If it runs, then do all the maintenance stuff above. If it doesn't turn over, then put a big wrench on the crank and see if the motor turns at all. If it still doesn't, then pull the plugs and try again.
Good luck, hope it cranks right up.