So, a couple of questions on the part highlighted below.
1. Do they have a proper name?
2. What are they actually meant to do?
I have a feeling that during the repaint and clearing of my playfield at least one of the holes where these are fitted might have been covered up. Just wondering if it's worth the hassle of sorting out so I can refit them in place or if they even serve a purpose.
I don't recall seeing them on more modern machines.

1. Do they have a proper name?
2. What are they actually meant to do?
I have a feeling that during the repaint and clearing of my playfield at least one of the holes where these are fitted might have been covered up. Just wondering if it's worth the hassle of sorting out so I can refit them in place or if they even serve a purpose.
I don't recall seeing them on more modern machines.