Ok, so I've been checking the stats after Mevericks info and here it is:
Tsunami Reef - 3 Mavericks
The White Flats - 1 Maverick
Red Rock Bluffs - 3 Mavericks
Dustbowl City - 3 Mavericks
Drownington Cove - 3 Mavericks
Since I have 13 out of 15 Mavericks available and there is only the Rainier Peak to unlock, I assume the remaining 2 are there... one is the hovercraft Art's got, the other one I don't know
Also I don't know which of my vehicles are Maverics (only those I remember getting) or where they are available.
I think the missing mav is that hippie VW bus, it would be to the very right next to the hovercraft in your vehicle selection.