For those not familiar, the DoD Acceptance Stamp was a 1/2" box with the flying eagle under 3 stars. The eagle is holding 3 arrows in its talons. This stamp was used for sure on M1 Garand stocks after about 1952 or 1953.

A friend of mine has come up with some of these OLD ORIGINAL stamps, and one of them is very tiny, the box is only 1/8". These are original stamps used by an armorer from Rock Island Arsenal.

This 1/8" stamp shows significant wear, and the hammered end shows major mushrooming, this tells me it was used to stamp metal, not wood.

I am not aware of any rifle parts ever stamped with the DoD Acceptance symbol...does anybody have knowledge of its usage?

Yes, barrels. I worked at RIA; (in TACOM). Of course, we didn't make anything; JMTC is the agency that makes stuff, and years ago, they made barrels for M1s, M85s, and others. They also made M85 MGs. Most don't realize there are many different organizations on RIA from the National Cemetery at one end to the Corps of Engineers at the other.
And 99% are just offices full of cubicles and computers. Only a very small part is the actual manufacturing center. (You do)
Another question is how did that guy get possession of those stamps?