a/c compressor spacer?

[nuc]

Is there a spacer that is supposed to be used when installing an a/c compressor? I see the first part listed as this in the gn/ttype listing of parts numbers. It lists the spacer as being .030". When I redid the a/c a spacer did not come off. Could this be why I've got a low speed vibration/growl when the a/c clutch is engaged?

Thanks

 

[nuc]

ttt