Depending on the manufacture date, it may not have a serial number.
Welcome to the FTF community and thank you for your service.
When you get a chance, head over to the new member introduction area and introduce yourself to the gang.
“If ye love wealth better than liberty, the tranquility of servitude better than the animating contest of freedom, go home from us in peace. We ask not your counsels or arms. Crouch down and lick the hands which feed you. May your chains set lightly upon you, and may posterity forget that ye were our countrymen.” ― Samuel Adams