I had to remove the metering oil lines from my engine yesterday and I'm looking at the parts fische to get the part number for the copper crush washers and noticed that there appears to be a gasket on the face of the pump, where the lines attach. Should this be replaced too?

 

Yes. IIRC it's an orange oval shaped rubber gasket. There is also an X shaped copper crush washer that is for all 4 of the oil lines and then the 4 individual copper crush washers.