Royal Gun Works was a trade name on shotguns made by Anciens Etablissments Pieper in Belgium from 1905 to 1957.
By the serial #
What does this gun sell for?
1905
Impossible to answer without the serial number
This gun was made in 1989
Blue Book of Gun Values
If the shotgun is a hammerless double, it is a Baker Model produced in 1899 (per Dixie Gun Works, Ithaca Serialization Guide) That serial should be a 1926 production NID. sales@countrygunsmith.net
Try Midwest Gun Works.
Try on line auctions, gun shops, gun shows, pawn shops, estate sales, garage sales, MidWest Gun Works, Shotgun News, egunparts.
The value of any gun is based on make, model and condition. We cannot tell that from the serial number. You need a hands on appraisal. Take your shotgun to a reputable gun dealer or gun show near you.
Lender's royal service # 117709
The serial of you Parker shotgun did not print in your question. But to find a date by serial number, there is a Parker Gun collector website that has a list of serial #'s and date of manufacture. The website is : http://www.parkerguns.org/