Yes, there are two sealing rings on the pump stator. I just air checked the unit as I did on the build and the servo's apply along with the clutch packs when pressurized. Then verified the pump clearances and they are .0035 with a depth mic and and the paper to housing clearance test is good.
When Installed, I filled the torque converter and the trans mission. I did light it off in park until the engine was timed and idle set as its a solid flat tappet build. The fluid was foaming so the unit was cycled to neutral and topped off again.