$1600 is probably a fair price if the playfield and cabinet are in good shape, and the game fully works. It really depends on your area, and how often games come up. No topper sucks, but many were decapitated by doorways. There is a reproduction in the works but it will be $2-300ish once it's available. The machine is probably also missing the 8 flasher sockets that are covered by the topper. Inspect the mpu for battery leak damage (keeping in mind the guilty batteries might not be the current ones). Go through the test menus and make sure everything works: displays, lamps, coils and flashers, sounds and speech.

The base is offered by pinbits: http://www.pinbits.com/index.php?main_page=product_info&cPath=13_44&products_id=380