All I know is that without a long bed CNC mill the job would not have been easy - it wasn't easy anyway!
One might seriously question if LAC had a CNC Mill. As a retired Machinist Modelmaker I can assure all that CNC mills are not only for high production, but are indeed capavle of making a lot of complicated contours, not easily made on conventional equipment.
This rib however requires only a straight flat cut & should be readily handled my any milling machine with enough bed travel to accomafate it.
I do note though Glenn did a fantastic job on it, my compiments to him.