The local Cummins parts house, FJM Trucks, called a pump rebuilder and got me the answer. I described to the rebuilder on the phone what the parts looked like. He told me the tiny hole in the piston faces down into the bore where the control valve (pressure regulator) sits. The rebuilder says that guys that play with pump pressures have this happen more often. But it happens in stock pumps as well. The clip goes in only until it’s flush with the bottom of the control valve. The top of the control valve can be pounded down with a drift and hammer to increase the pressure he said. Also he mentioned that if I did that the pump would have to be calibrated again. Now worries here, this old girl is staying stock. The pic shows the correct way this valve goes back together.