I'm not 100% sure but wouldn't dozer tanks be assigned to the HQ Company? Looks like Hell Kat's fender markings show an HQ.
Typically for an M48/M60 equipped Armor company, the XO's tank was the blade tank. Ralph Zumbro, the author of Tank Sergeant, mentioned that the tank that he was the TC for, after Tet, was A/1-69's dozer tank in A/1-69. He never specifically mentioned that it was the XO's tank but did mention that his "wingman", Cheyenne Black, in the A Co HQ tank section was the TC for the Commander's tank.
Now with tanks being assigned to an Engineer Battalion, who knows what company they were assigned to or what vehicles that they ere replacing - Maybe CEVs...
Chalk it up to another mystery in the fog of the Viet Nam Conflict.
I agree, keep/run the hydraulics and keep the HellKat markings for a unique M48A3