Early Oil Pump Question

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The 1929 Sport Coupe project car I bought several months ago came with a rebuilt engine, which I have been inspecting recently. I don’t know who rebuilt it or when, but suspect it’s a Sears engine from 30 or more years ago, based on the history of the car.

The original block number was ground off the block has been re-stamped. The oil pan is the 1928 style with removable round oil pump access plate on the bottom. The oil pump is also unlike others I’ve seen.

The picture shows two major differences - a cast bottom plate with no spring or clip and two slits at the top of the housing for the oil to exit..the pic shows only one of the slits.

The engine has obviously been rebuilt with all new pistons, rings, valves and springs, and the oil pump has new bushings, gears and main shaft. The engine is spotless inside and has clearly never been run.

My questions are - is this an early 1928 pump ? Should I replace it with a later style pump for better oil flow, or will this one be fine ??

Many thanks - Jim