Beach - you‘ve got it backwards:
The G-Wagon was a military design first, the Mercedes G-500 is the civvie version which followed (similar to the civvie Humvee‘s you see driving around town - military vehicle first, civvie "Look Cool Factor" second).
There was a competition held, and GM withdrew their bid - this left Mercedes the winner by default (once again, Liberal party politics - Herb Gray was the Deputy PM at the time, and Chrysler is in his riding, and Mercedes is part of the conglomerate ...)
Having said that, I‘m led to believe these vehicles are actually made in Europe (which probably explains why they were able to accelerate their delivery).
I‘ve ridden in an earlier 2-door variant, and I‘m SOOOOO relieved to see we bought the 4-door (the back seat of the 2-door was a ‘death trap‘) - my German buddies were adamant that they preferred the 4-door, too.
Now, if we could only buy enough of them for the entire Army, instead of having a split fleet ... sigh ...