These vehicles in my day were double articulated in that the prime mover ( Gun Tractor) carried the wreaths and flowers the limber ( Box on wheels that would carry the ammunition for the gun ) would carry the coffin on a special frame built over it, then the gun would be behind the limber. A unit that I served in back in 1964 had an international AR130 as the Gun Tractor It was the only AR130 that i ever saw in service over the years they have used Dodge 1 tonners, Landrovers Ser 2a & 3 the ser 3 was converted to Auto gearbox. There were only a small number made, I think one for each command (State) Although I never got to driver one I have transport the gun and limber from Brisbane to Lismore on the back of a truck.
Hodgo