I was on active duty in the '80s and in the Guard through the '90s, with my Guard unit keeping M1911A1s until the late '90s. These were Infantry units, so it might have been different for MPs.
I'm not an expert, but basically all 1911A1s used by the US military dated no later than the end of WWII. They were inspected periodically, and met military standards, but I'm sure they had all been rebuilt at some point. All the ones I saw had the brown plastic grips.
Pistols seldom left the arms room except for the range, with only assigned users doing the qual course. There were always far more weapons than assigned users (especially in HQ companies, which had many more pistols than line companies). Other than range activities, pistols were almost never issued for training exercises, for fear of loss. A few would be issued for guard duty or payroll, but generally they did not go to the field (except for real-world missions).
I once witnessed a failure on the range, where the slide broke in two (luckily not injuring the shooter). I also occasionally saw what I know now were early two-tone mags. A fair number would be Colt 1911s upgraded to -A1, but the vast majority would be WWII manufacturers.
So, basically CMP .45s would be old, but milspec, fired not much per year, but for many years. Most will be in decent condition, but well-used.