NEMA 34 motor mounting question

I about to mount a NEMA 34 motor, it has a square front plate with four equally space mounting holes.
The hole diameter is 0.218 which seems sloppy for 10-32 and too tight for 12-32.
I feel like I should be using 12-32.
Is it normal to expect the end user to drill these mounting hole to suit !

Next question:
The front mounting plate is not complete flat, it has a raised portion (0.06") and round (2.872 diameter) .
When I mount this to a plate I will have to remove that same amount of metal ( and a little extra) to ensure the motor is bolted flat to the mounting plate.

What is the purpose of round raised portion !
To me it would be better if front was flat ?
I expect there is a good reason for this strange arrangement.... May be to make more work for machine shops !

Thanks for any help...
Hans W