I finally found the picture of the missing alternator plug plug that goes in the V shaped wedge. Upper right hand corner of picture.

I asked about that recently and the brain trust said there’s only supposed to be one. Something about no plug on the lowest “V” to facilitate drainage.

The OE alternators in my parts stash have both plugs installed.

One of them still has most of the paper gasket between the back cover and the body.

Well that should answer the question then. You need both plugs. Problem is they are NLA. They are never included in the rebuild and no one mentions to keep yours. Mark at 914Rubber is going to make the gaskets at some point.

NOS rear picture