Hi Guys
I have never quite understood why these parts had to be beefed up. Other than having one of the flange bolts get loose and hitting of the mounting bolts what could break them.
Basically all this rear cover does is seal the bearings, hold the seal for the drive flange and hold the speedometer gears.
As the speedometer take off is not used on the CMP you will need to find or make plugs for the holes.
Below is a picture of two of different styles of end cap I've seen, also have seen the aluminum or pot metal.
Cheers Phil