rear cam plug

i went to install my cam and noticed that the plug is not in the back. I have it, but i wanted to be sure that i put it in the correct way. The outside of the plug is tapered. I am assuming that the smaller side of the plug goes into the block first, but wanted to double check as the book says if this is bumped during the cam installation it will result in a major oil leak.

Also, my book says that earlier small blocks had a tab that is bolted onto the thrust plate to lubricate the roller chain, while later blocks have a bolt with a hole in it to provide lubrication. My block is a 68 and i assume that it would have the tab. If this is the case, in the last 6 years since i disassembled the engine, i have lost this tab and need to get a replacement. I have not had any luck looking for one. Does anyone know where i can get one?

Thank you.
Steve