Difference between Cone cam covers

[1970 XLCH]

I would like to find out the difference between the 70-72 & 73 - on , cam covers ,except for the obvious " side oiler " & "end oiler" . I have a 70 cam cover that is an side oiler . It has a hole in the bottom of the pocket ( boss ) that the pinion bushing is pressed into . The hole ( approximately 1/8 dia. ) is at the bottom ( past the bushing ) pointing to the pocket where the welded sheet metal baffle is , which would let oil out to that chamber . Is this factory ? Anybody have both covers that they could take a look at ? Thanks, Mike

[vph-d]

Service Bulletin #647 from 4/73 addresses the difference between oiling systems and cam covers. I don't know how to post, maybe someone else can post it for you.
VPH-D