My 520 is a few years older than that 87, and I was offered $500.00 for it a couple weeks ago. I wouldn't part with it for the price of a new one I love it so much. Check the frame you should be able to tell how the lugs have held up, check around the frame openings for signs of rust, eyeball it to see if the frame is straight and I'd say considering the price of a tune-up and some new tires, you couldn't go wrong as long as the bike fits you I'd snatch it up, and quite honestly at that price, I would snatch it up and have two of them in a heartbeat if it were local to me!