Stock rocker shaft oil hole orientation

The wear patterns say what they are from. The left one is for the hydraulic lifters and stamped rockers... the narrow area in the middle of each rocker wear pattern, where there is no wear, is from the formed groove along the bottom of the stamped rocker. The large hole looks normal from what little I have seen of those shafts.

OP, you have it correct about the right hand shaft. The wear pattern on the right looks to be for the 273 adjustable rockers for solid lifter cams; there is no 'no-wear' area in the middle of each wear pattern. That hole on the side would be for the squirt hole to the pushrod & adjuster area. Mine have a 2nd hole pointing downward plus banana grooves. But perhaps some of those solid lifter shafts had the lower hole omitted.