http://www.ebay.ca/itm/PETER-WELLER-...item19d470128d
Considering this isnt being claimed as the original or one of the prop guns used in the film, and is still fetching an asking price of $2500, its safe to assume the hobby shop would obtain a PSA/Letter/Certificate of Authenticity to go with a signature on the item and resell the item as a collector's piece. $500 isn't bad at all if it has no intrinsic value to you.