GReddy944

I bought a 1987 944 and replacing the gaskets on the oil cooler and replacing oil pressure switch, ( just preventive maintenance and almost everything's been replaced but that) my oprv is an old style 3 peice with 17mm nut, I know after 86 they are 1 peice and before they are 3 peice, doesn't look like the motor has been replaced either, is this normal? I even bought a new style alignment tool which I'll try out tomorrow and see if it fits, oil pressure was always at 5 and 4-3 when shifting.