Though not rare, the original Forte is one of the more desirable models from that era of Klipsch. They usually command a few dollars more than the Forte II. Check
http://www.audiogon.com to get a ballpark idea of what they might be worth. You would be much better off selling them to an end user than a shop who would resell them. If you sell them to a shop, expect to get less than half of what you could sell them for otherwise.
-Dave