Oil Gally Plug Locations

Ok so as I was sitting around reading the Aug edition of Chevy High Performance. I read the article on, ( How to Build Your First Engine) It staits that I must install the plug in the deck surface on the driver side at the rear. If u forget this plug, it cannot be installed with the head on the block.
I built the chevy 350 2yrs ago I dont remember if I did. The Machine shop installed all the rest of the plugs, But I did,nt know about this one and the one on the #5 main cap. I can check the main cap plug cause the Motor is still on the stand. I just got done making the Tbi intake fit by grinding the 4 inner holes and used Hi zute gaskets. I will disasemble it if I have to, or is their another way to tell. Or are they refering to the dowls in the block that line up the heads?
Also how much extra lift do u get by installing 1.6 ratio rockers.
My cam spec's are 218/218 dur@ .50" .458"/.458" lift with 110 lobe sep. Its a Lunati Bracket Master2 cam kit.

Thanks- Travis:CRY: