Yeah I believe the days of trusting AC Delco parts at face value are over.
However, good suggestion Bo! As we all know the Harrison V5 compressor is a variable displacement compressor meaning its operation will vary with engine load and other conditions. It is always engaged unless you go to WOT, etc.
Is this sound an actual grinding noise or a moaning sound that varies? V5 compressors will motorboat when the charge is below what it should be and depending on temperature and humidity conditions even though cooling may feel satisfactory. Anyways the compressor appears to be the most likely suspect since the noise is gone with A/C off and it doesn't sound like the clutch bearings.