RRAD marking on M1 Rec'vr

Just received a M1 Garand that has been built up to a match rifle: Krieger barrel bedded rc'vr and screwed and bedded forearm. It is built on Rec'vr no. SA 5928708. Only marking are on right front tang: F6528281 and barely visible in 1/2 inch hand written letters RRAD 11-65. Any guesses.

Krebs

Red River Army Depot and if my memory remains Texarkana, Texas.

Thank you Skip.

Krebs

I have the same markings on my buttstock.

My IHC is marked by RRAD 1-65 on the right front receiver leg just like yours.