Update to post
Talked to Remington today.....The Sporting Clays 11-87 uses the same magnum receiver as all other 11-87s, the only difference is the Sporting Clays is finished a little nicer, and the wood is better than the standard 11-87s. The reason the SC version only shoots 2 3/4 is the barrel only, so you can swap out with any standard 11-87 barrel if you need to shoot 3" out of it. The difference lies in the gas tube, supposedly the standard 11-87s have some trouble with the lower powered loads, so the gas system is different on the SC barrel to ensure reliable functioning. If I wanted to add a new barrel, I would have to change or modify my forend to accept a full contour barrel, as the SC version uses a light contour target barrel. Not a big deal at all, forends seem pretty cheap on Ebay, but finding one with matching wood may be a problem, since the 11-87s with full contour barrels seem to have a little less quality in the wood. IF I were to change barrels it would be for a 18-20" for home defense, and synthetic is always a cheap option.
Thanks for all who replied!