Well, My engine is a 72, is it an issue? Here is what my new plate looks like, do I need a plug? The old set up was the 4 bolt plate and the oil slinger on the crank.
The original thrust plate was ground on the mating surface of the block to seal the galleries. Since you are there I'd remove the tensioner and see if there are plugs in the Galleries. If not get some from a dealer and install them. The Tensioner is basically made of sheet metal and not designed to seal the galleries.