I've been doing research on a potential M123/M747 scratch build. I had considered the M123D because of twin mid-mounted winches, but I read that the M123-E2, also with mid-mounted winches, was specific to the M747 trailer. I did an internet search of "M123-E2 military trucks photos" and found both photos and movies, just in case you might be interested.
In Christ, John Autry.