Use your eyes; look down the stock to see if its actually bent or if its just a local rub that you would simply sand on the inside for slide clearance. Put the carbine in the stock and see how the barrel lies in the nose. If its about centered and the receiver fits the same on both sides, I don't think the stock is bent. Lay the stock on it's sides and see if there is daylight under it on one side and not the other - that would represent a warped stock which may also be twisted. All that can be straightened out. If the stock is bowed, I would find the center of the arc and work on the concave (inside bend) side with steam, starting at the center and working my way out the ends of the bend. Over a few days, as that side swells, it should force the stock to straighten. One way to steam is to place a wet cloth on the work area and apply a hot iron to the cloth, which forces the steam into the wood.
BTW, that's a very interesting hand guard you have there!