I was a competitor out at Camp Perry from 1989 to 2010.
When I went to camp Perry in 1989 I used a M1, and the ammo supplied for the NTI and P100 was M72 FA59, clipped. What a let-down, as the clipped lots were not that good. This is when the M1A/M14 shooters were being issued M852 white box dated 1988. The reason for this memory will be apparent in a moment.
So if you went as part of a club team, as a civilian you could draw a M1 NM or M14 NM and use what ever ammunition was being issued at the line (ammo was free once you paid for your score card, which was 2 or 5 bucks). This information was included as part of your competitor packet. I never saw a shooter draw a M1 in 1989, 1990, 1991 or 1992 as the ammunition issued was really the dregs or at least the possibility existed. But you could have done so if a shooter was so inclined. One had no idea what lot or year was to be issued in 30-06 before the match, and if you went to the Inter-service regional you might have been issued something else altogether. As you had to use the issue ammo it was such a detriment to good scores that no one serious used the M1 rifles prior to them allowing match ammo of your own vintage.
The last year you could draw a rifle like that, according to my memory was in 1993 or maybe 1994. The next year you had to pay for your ammo (no longer free) and the rifle issues were no longer allowed, if my memory serves me correctly.
The rifles were all property of the Army, but were not really current rifles in the Army inventory, being DCM held. The DCM was part of the army, a colonel in charge, not like the CMPtoday. They were simply there for use by the civilian competitors. No Army competitors used M1 rifles, they all had M14 rifles up until 1993/4 when the change over to the NM16A2 began. The last team to use the M1 rifles was the navy team, and the last year they used them as a team (not individuals) was in 1983, the next year they shifted over to the M14. In fact in 1983 the Navy Annapolis team used M14 rifles provided by the Marines. The M1 Garand vintage matches did not start until 1998 if my memory serves me correctly, so they would not have been used for that, in any case NM arms were not allowed in that category.
So the records indicate they were on issue to the DCM for marksmanship support or issued to a state association. After the DCM went away (Feb 1996) and the CMP took its place, all arms had to be transferred to the CMP as all the DCM rifles on issue were still army property. This occurred in batches which in the case of your rifle happened in 2007. It was likely never returned the AMU post 1993, it just moved from one stock category to another, as NM rifles had a separate NSN than the regular M1 Garand.
By that time I very much doubt many NM M1 rifles were still on issue to state associations, they mostly had M14 NM rifles by that time. Got mine in 1992 and gave it up in 1996, I think the CMP called them all back sometime around 2000.
If you need more precision than that I can go back an pull up my old competitor packets, I am pretty sure I have them though at least 1999.