Not a great idea
The perf. plate folks retreat the newly ground design to Rockwell harding.
You might weaken the oe unit by grinding on it, what if it broke off and a chunk fell down into the governor and wrecked you Injec. pump? (read 2000 plus labor to r&r it).
Does $250-300 seem cheap for the correct plate?
No flame, just food for thought.
Good luck
Andy