What he said up there ^^^. Do it for free- hobby. Charge for it- you are gunsmithing, 01 FFL needed.
My local smith polished and hot blued a S&W Mdl 36 for me- $130. REALLY nice polish- did not round over sharp angles, dish out the screw holes, or mess up lettering. Good polishing is key to good bluing. COLD blue of an entire gun is like kissing your cousin- better than nothing, but still leaves a lot to be desired.