The Apollo service modules weren’t jettisoned until the command module separated for Earth re-entry, so it wouldn’t be in circling the moon, though it could be in a highly elliptical Earth-moon orbit that could wind up back at the moon at some point. (I dont recall if the service modules were supposed to burn up in the Earth reentry of not.)
The LEMs were left in lunar orbit but I thought they all rapidly decayed and were used for seismic measurements with instruments left on the surface.
You’re correct- it was whatever they left behind before departing the moon to head back to earth. Was that the LEM?
Anyways, I have read that the one from Apollo 11 is still in orbit.
The next ones they crashed ito the surface to record their impacts in the instruments they left on the moon (to detect moonquakes).
I also read that the moon ‘rang’ for 3 hours afterwards, suggesting it is hollow.
So it is probably filled with aliens who watch us through little peep holes.