Removing a rear rad can be a real nightmare. Friend's Diplomat , rad shop had to cut the rear cap, after phoning manufacturer to confirm that cutting was the only option short of complete removal, of the rear cap , to get his out.
They did a great job of keeping the cuts straight, and from 10' away you can't tell the seams aren't factory.
Another member with an 04, Freightliner , W/Cat , Sportscoach who has pulled his rad is the only person who will be able to tell you for sure.