The copper color is the copper/lead alloy bonding metal between the SAE 1010 steel backing and the lead/tin overlay. The last layer is a flash layer of tin that is used as a dry lubricant. The flash layer of tin is polished off with Scotch Bright by some engine builders before assembly. I have always polished it off and used a good assembly lubricant such as Sealed Power 55-400 or Lubriplate 105 assembly lube.
That is the normal appearance for so-called tri-metal bearings with 100,000 miles on them.