I'll assume you maybe talking about one like this; Model 01975 Colt MKIV/ Series 70 Government in Satin Nickel with Blued/ Black small parts. You can clean the Satin finish somewhat using a CLP like Remoil and gently scrub it using a soft toothbrush.
These are not super rare or scarce but do have some collectability value. Bottom line, its your pistol so if the gunsmith won't do the work you want go elsewhere. Good luck