Comp cams xe268h for 318
2 holes are in #2 and #4 cam bearings for the oil to flow through the cam journals on those positions, on its way to the heads. Yes, it is all pretty obvious. The later ones would have that also for an LA block.
Look at the cam's journals on #2 and #4; you will see the 2 holes in those 2 journals for the internal passage through those cam journals. That forms an 'oiling interruptor' that allows the oil to flow to the heads only about 5-10% of the time, when the holes line up with the mating holes in the block and cam bearings.
When you install the #2 and #4 cam bearings, check the block to make sure those cam 2 bearings' holes line up with the holes in the block; #2 should have the 2nd hole to the driver's side passage (to that side's head) and #4's 2nd hole will be on the passenger side.