If it was properly stored, some fresh petrol and oil might be all it needs. A friend once bought a seized Comet which we broke loose with a drilled out spark plug hooked up to an air compressor.When we put the old spark plug back in, for a lark, I opened the fuel tap, tickled the carb till it was full of what smelled like turpentine, kicked it twice and it was running! Only then did we decide to change the old fluids out. The thing ran a few years after that before it needed a rebuild to the top end. He still has the Comet and we still laugh about it thirty years on.
Cheers, John