3.2 Oil Galley Plugs - Threaded?

[schnellmann]

This might be one for John, Steve or Henry, but any information from those in the know would be appreciated. BTW, I searched but did not find anything definitive, and I searched the parts diagrams as well with no luck. I didn't see the press-in ones in the diagrams.

If I wanted to have my machine shop pull the 2 top/right galley plugs (behind the fan and the flywheel) and tap them, what diameter/thickness plugs would be used and where could I get some?

I understand that they must be flush with the case on both sides so as to not interfere with the relief piston, fan, flywheel (respectively) or the oil flow generally.