Nick, yes, they are for the 2 piece Cowlings. We had them right to the end of our local production in December 1981.
Thanks Moke Spider, I will source a timing cover without the breather just in case I have to take out the engine in the future, probably a lot easier job to when engine is on the stand. But I think I’ve manage to work it out with the one piece later cowl. It’s just part of the process when trying to use parts from different era cars to all fit and work together.
Just keep in mind the One Piece Cowling is for later Cars that didn't have the Cowling on the body. You should be able to get it all in, but is a 'neat' fit.