David; You won't have any problem "cracking out" whatever is in the sealed slab. Coin dealers do it all the time.

At major coin shows at one time, the bourse floor was littered with remnants of slab holders that had been cracked out behind dealer's tables with the hopes that by re-submitting the items they would come back re-slabbed at a higher grade from the same grading service ... or a different one.