Noisy A/C Compressor?

I have a 99 Intrigue with the 3.5 engine, mileage is 77k. I recently had a trouble code of P0410 set, which I cleared with a new relay in the fuse block. About the same time, a loud constant noise started coming from the area of the A/C compressor (the lowest point on the motor). Constant, that is, with the RPM of the motor. My service guy make a good guess that the compressor bearing assembly sounds as if it failing. He does not know if the bearing assembly is a replaceable part, as opposed to replacing the entire compressor unit. I am continuing to drive as is, with the hope I can find some information from the group. Ideas?