Excessive (isolated) 273 Adjustable Rocker Arm Tip Wear: Diagnosis & Repair?

Rocker Arms Unlimited will reface those types of rockers for about $13 each if you can't get it done locally. They will bush them pretty cheaply too if the bores are egged out.

Regarding the hole, some came without. I don't remember the theory behind it, but I know some people would block the holes on top of the arm.