All valid concerns. If you study the specs here, you'll see they came in walnut, oak and black. Familiarize yourself with the dimensions, component types, etc. so you can see if the one you're looking at matches the specifications.
As for value, search eBay completed items, and do a search here in the Garage Sale forum. KG-4s are very common, and the prices are variable, of course depending on condition, location, etc.
Be sure to check that all drivers are operational (place your ear close to each while playing music, but don't turn it up too high!). Also you want to notice the condition of the foam surrounds. BTW, the "woofer" on the pack is a passive radiator.
Hope this helps. KG-4s were my first Klipsch speakers, and I loved 'em!