Just a suggestion:
Why not see if they'll let you put a deposit on it so you can take it to a locksmith and have the triggerguard lock removed. If they won't do this perhaps you could accompany one of their staff to the locksmith. Once this is done you'll be able to break the gun down and examine the underside of the barrels plus the water table.
Jim

The 2nd Amendment IS an unalienable right.