The Rocker shafts are PRW that came with the kit.
The first set had oil holes on the bottom inline with hold down bolts.
The second set are drilled straight through with oil holes top and bottom.
Probably to make them fool proof.
Or maybe to help with oiling.
Oil hole in the top is of no value, you want to get the oil to the rockers main friction point, which is obviously the bottom. Widest clearance between the rocker and the shaft will be at the top. If the oil can escape there first, then it will.
You then want to spread oil across the bush, that's where a small oil groove comes in. Then you need to make sure it's getting enough oil.