Actually, It was once commonly recommended in cycling manuals (in the 1970s) to lubricate freewheels with light grease in the bearing races when overhauling or rebuilding them. I just thumbed through an old Glenn's manual from 1973 to check, and it shows photos of a disassembled freewheel body being really loaded up from a tube of white Schwinn Cycle Lube grease.

I've had some brand new freewheels which appear to have had no grease or oil in them at all (Regina comes to mind) and the bearings could be heard rattling around loosely when simply shaken. Others were very tightly packed with grease and super quiet. It did not seem to matter.

So long as it works, I'd just leave it alone. Enjoy the silence!