Not all rifles and shotguns HAVE a serial number- they were not required by US law until 1968. Contact local law enforcement, and give them the make, model, caliber, description, any unusual marks, photos of the gun if you have any- and hope for the best. A serial number would greatly improve the chance of recovery, but you may get lucky without one.
No way to answer without the serial number.
Impossible to answer without the serial number.
Impossible to answer without knowing make or serial number.
A serial number is meaningless without knowing the manufacturer.
Impossible to answer without a serial number.
Impossible to answer without a serial number.
Impossible to answer without a serial number.
No way to answer without the serial number
No way to answer without the serial number.
Impossible to answer without a serial number.
Impossible to answer without the serial number.
Can't be answered without the serial number.