Multi-passenger vehicles?

Is it possible to have a vehicle that, when you spawn from the spawn menu, has three different seats that you can enter? (As opposed to having to create two extra seats and weld them to the vehicle.)
Furthermore, is it possible to have a passenger seat that the player can shoot their own weapon from (Like the Weapon Seat addon) and a gunner seat in which the player fires a rotating turret?

Vu-mod

Is Vu-mod’s code open-source? As in, do I have to ask the creator for the code if I wanted to make my own vehicle with it?