If you're going to buy at a gun show, I would wait & see what the sellers have to offer. Go check the completed auction on AA/GB to get a good idea of how much they are selling for.

Yes there is more demand for the shorter bbl, and they are slightly more practical; but, if you are on the fence about it, I wouldn't let the extra 1 7/8" become a deal breaker. I'd rather have a good deal on an 8 3/8 that was in excellent cond. than an average deal on a 6.5" in good condition.