CM2250 Rear Structure Leak

[Truckdriven]

I have a 2012 kw W900B with a CM2250 ser# 79502726 620K miles. I pulled things apart to fix an oil leak at the rear structure gasket. I can see slight wear on the aluminum flywheel housing at the top right side exactly where it was leaking. Do this need to be machined or how critical is that?? Also since I have the pan off should I be shimming the oil pump regulator? If so how much?