The serial number on a Rock River AR-15 lower receiver is typically located on the right side of the lower receiver, just above the trigger guard and below the magazine well. It may also be found on the rear of the receiver, near the buffer tube. The exact positioning can vary slightly depending on the model, but it is generally engraved or stamped into the metal. Always consult the manufacturer's documentation for specific details.
Barrel or receiver or both.
Receiver.
Receiver.
It depends on the actual serial number, which is located on the receiver.
The serial number is located just forward of the loading port on the bottom of the receiver.
Bottom of the receiver
On the receiver
Check the receiver.
CHeck the receiver and barrel.
Try the receiver or butt
Look on the receiver and barrel.
Check the receiver.