There's a world of difference between custom framing and off-the-shelf frames. If you have it professionally mounted, there's less risk of the uncut sheet getting damaged over time by such things as sun bleaching and moisture causing the sheet to adhere to the clear surface or the backing. It's worth doing if you have truly valuable uncuts. You may also be able to find a framer willing to set it up so as to be visible and hangable from either side.