If I were you, I'd pull it when you do the motor swap and send it off for a heavy duty rebuild. Any decent shop I'd recommend will do the HD2 kit or equivalent as part of that rebuild anyway. And they'll do a lot more than just replace wear items and seals. With that mileage, stuff like the pump and valvebody (worn bores, etc.) will need attention too.
Where are you located? I'll see if any of the good shops are near you.