I've got an 80's SR SemiPro with a Shimano 6 speed freewheel. I've rebuilt the wheels and I'm ready to put the freewheel on. Only I notice that the chrome or nickel plating is peeling off of the smallest cog. I bought a replacement off Ebay, but it's a recently manufactured 6 speed freewheel that is really cheap compared to the old Shimano. The pawls sound like they're grinding coffee, while the old Shimano still spins like butter.
So any harm in running the older cogs aside from perhaps increased chain wear?