A couple of thoughts:

1. Games on location are often not owned by the location, but instead owned by a third-party operator that is responsible for maintenance and splits coin drop with the location. 2. Since the game is on location it was probably playable at some point recently. It may be off because of something simple like a rubber ring breaking and the ball keeps getting stuck or an important switch not registering, but the operator hasn't had a chance to fix it. If it was recently and only needs minor work, its value is more likely to be $5,000 than $500. 3. Even if it has been broken and not working for years, its value would heavily depend on the cosmetic condition. A non-working machine with a great cabinet (artwork without fade, no dings) and no wear or damage to the playfield would still probably be worth closer to $2-3,000.

It never hurts to ask, though!