Blown head gasket?
 

I have a 2015 Ford Transit with the 3.2 I5 powerstroke. I have a blown head gasket. #3 cylinder had done coolant and rust coloring on the piston that wiped out, but the intake valves have a more significant rust color around the sealing surface. Do I need to take it to a machine shop, replace the valves, or just try to polish them up some?