need help finding correct bumper stenciling

[Tylos]

Hello to you, I would like to attribute my Willys MB from 10/26/1944, to the 704th Ordnance Light Maintenance company of the 4th Infantry Division which set foot on the beaches of Normandy in France, but I am missing a few details.
For the stencils:
In second element, after: 4 I and -704
on the bumper of the vehicle, you must put: ORD or only: -O?
And for the 3rd element after the Star, what exactly did the professions represented by: MT (maintenance) and RP (repair) correspond to during the Second World War?

I am a machinist, metalworker, amateur blacksmith and I repair tractors, so I want to stick to reality for the Willys stencils.

Thierry.
France