Guys, the screen with the dimple was not original to the early cars. Porsche developed that screen during the 1980's due to oil scavenge issues in the SCs. That screen looks like this:
Drain plug would be on the drivers side.
The 1972 would have originally come with a screen that looks like this. No dimple, so there is more flexibility in mounting the sump plate. I think the drain plug is usually positioned along the center line towards the rear of the car, but it could be on the drivers side as well.
So it really depends on whether the oil screen has been updated to the later style.
Mark