The galley plug your talking about is a plug on the
oil galley that feeds the lifters. I don't think it has anything to do with the cam gear and distributor gear, drilling the hole in it will shoot
oil on the backside of the upper timing chain gear, the splash from that will lube where cam gear/distibutor gear mesh....otherwise, the cam gear/distibutor gear are lubed from the
oil slinging off the crankshaft at the #1 journal....
I'm not sure you could drill the hole at enough angle to directly shoot oil on the cam/ditributor gear...
It can't hurt to do it though and I do it on my engines just for adding oiling....
David