Drop one of those little flashlights down the barrel. If it has rifling it should be obvious.
What do you mean when you say it has been "cut down"? Has just the stock been cut, or the barrel as well? If the barrel has been cut, what you have is a mere source of parts: the lock, trigger guard, buttplate, rear sight, and miscellaneous hardware.
These can be fairly valuable to someone building a hybrid original / repro gun. Keep in mind that new stocks are available from Dunlap Woodcrafts, and new barrels from Whitacre's Machine Shop.
I built just such a hybrid M1842 musket. The stock and barrel are new, but everything else is original. I actually like the new barrel in preference to an original barrel, because this way I know that it's 100% safe to shoot. With original barrels, you never know because of possible internal corrosion.
Unlike the Italian repros, Whitacre's and Dunlap's products are made exactly to the original specifications.