66 Dart GT HT Whatsitgonnabe?

dust cover holes - - yep - just for holding the dust cover - there may have been a brace (I can't for the life of me remember if it was on the left or right side) that attached to the one on the right - but most people don't reuse it. Just put some bolts in there and move on. Your valve cover is likely on the wrong side - I had to mount mine so the breather is to the right and the PCV is to the left.

There were braces on both sides from the factory. They can't be used with some headers and most people leave them off...