IBM curious questions about IBM master

[paradise]

Two curious things I noticed about the IBM works: firstly at each arbor on the plate where the arbor goes into the plate there are some cups which look like oil sinks but are not shaped properly and are usually facing in. My suspicion is that they are punched at each location during manufacture to help temper the metal as brass is strengthened through hammering.
The other thing is the small plates that hold the verge/crutch, I have seen them installed with the slot on the left and with the slot on the right and don't know and wonder if it makes a difference: is there a proper way to face them? I usually pull up a drawing on the IBM website and look at how they have them facing.
Anybody know the answers to these, any opinions. Thanks...Paradise

 

[ibm clock]

I had asked a question about previously about the indentations that look like oil sinks on the back of the plates. answer i got was about the same as you said about it being there to strengthen brass and they are not oil sinks.

As to the verge plates, I've seen them installed either way, not sure what is correct or not