It's a yes and no answer. Most of the vehicles are found in DTA\Data3D.pbo. While the config for them is found in BIN\CONFIG.BIN.
However, the vehicles and weapons that can in the later patches can be found in the addons and res\addons folder.
For example, the M1A1 is found in Data3D.pbo, but the M2A2 is found in addons: it is m2a2.pbo.
All the vehicles and weapons introduced after 1.30? (or is it 1.46) can be found in the addons folder. All the vehicles and weapons before 1.30 or 1.46 can be found in data3d.pbo.
I hope this clears everything up!