No,
trucks cannot load or tow guns in this game.
Your designated supply trucks in the supply platoon effect supply,all other trucks can only transport soldiers and their hand held weapons.
I find the non supply trucks in this game to be pretty much useless on the winter maps.
Alas NO... BUT this is GREAT way to move around (if you need too) weapons that brake down... like mortars and machine guns. For modern dlc's all the recoiless rifles! Transporting your troops with vehicles IS handy as no -fatigue points.. actually lets them rest. This is only a factor if for some reason you need your guys 2km away like corner areas of the battle.
In the game USUALLY the units with truck are your supply vehicles. WAY valuable when they still have supply's. SO HIDE THEM! After they are out... cheap transport for your battle tired infantry guys.