I think I'll post in here and quiet the riot and quall the speculation.
It is, in fact, the Badge of the MDO's, Military Driver Operators. My civilian counterparts. They wear a bluish grey uniform these days and a peaked hat for special purposes, usually an MDO 4 doing VIP or base runs. MDO 5's and 6's, who are the Heavy Equipment Operators and De-Icers, wear civilian clothes.
MDO's back fill MSEOps on deployment and do many of the mundane duty runs around base while the mil drivers do shift work and get the.....cookie on the floor.
If it was the green triangle with crossed guns or cannons, it's the old RCEME hatbadge {NOT very well liked by the EME guys}
"Don't think we're better than most,
Just better than you."