I've not had an old Hemi torn down, but all the other Mopar motors that oil the rocker shafts through the cam bearing only send oil up through the port once every revolution, when the cam port lines up with the oil port in the bearing.
If the cam bearing was incorrectly installed, the oil hole may be only partially open, which would restrict the amount of oil getting up to the rocker shafts.

What concerns me is that the design of the oil ports in the rocker shaft should oil the upper rocker first, but is not. I bought a new Chrysler 360 block once that only had the oil passage through the block drilled part way. The way I discovered that was on a long trip with the fresh motor, I bent the push rod on either #1 or #8 cylinder (can't remember which). What I thought was oil flow turned out to be oil splash from the cam/ lifter area. Motor had very high idle oil pressure. No oil was coming through the rocker shaft. There was enough splash to lube the rockers around town, but the long highway trip prevented the mostly splash protected rocker on that one cylinder from getting enough lube and tightened up enough to bend the push rod. I had to pull down the motor and finish drilling the oil passage through the block and replace the rocker shaft and the rockers and push rods on that one cylinder.

The reason I wrote all of this is because I want to know if the oil you see on the lower rocker shafts is from the oiling system or oil splash from the cam & lifter area? Pull the rocker shaft, pull the dist, turn the oil pump with a drill and a pre-lube tool, and rotate the motor at least 2 full revolutions. If the oil passages are open, there will be no doubt, oil will shoot out of the passage at oil pressure force. Once fixed, the oil shot out of the oil passage on each side past the front tire on my 35 sedan. I'm betting the oil hole in the cam bearing is not lined up with the oil hole in the block and the oil you are seeing on your lower rocker shaft is from splash.
Sorry Gene