I think I'll go the tune-up route for now and assess.
The AC is working fine and doesn't sound or feel unusual, so I'm leaning against that.
The AC system hasn't been touched since Dodge replaced the condensor and recharged the system long ago.
I haven't measured the system pressures, but are there products that allow you to add more oil or improve lubrication of the compressor?
Regarding the idle air control valve, can it be "cleaned" or is it a "replace only part"?
What should be cleaned (a moving shaft, for example)?