Where is the serial number on new elgin arms shotgun?

These were made many years ago, and may not HAVE a serial number. Serial numbers were not required by law on rifles and shotguns until 1968. Yes, it is perfectly legal to own a firearm that never HAD a serial number IF the law did not require it at the time the gun was made. It is illegal to remove any serial number from a firearm, or to possess one that has had the SN removed.