They were built from the early 1970's until approximately 2004 or 2005. Some are collectible some are not, but you your question can not be answered without pictures.
If it's a custom shop cue it may be worth something. If it's a production then I'm not sure. Look around the bottom of the butt cap where you insert the rubber bumper. If it's engraved around the bottom "CUSTOM SHOP 19??" then it could hold some decent value.
Here's one I had a while back, if I recall correctly I got in the neighborhood of $550 for it.
Great playing cues. The custom shop ones are the ones that hold their value as mentioned. But if you are looking for a player, you cant go wrong with any of them (minus the era where Paul had sold the business briefly)
Chuck