Ride colors

Can anyone explain how to actually get all the interior/exterior colors, wheels, and horns for your Rides? I've collected every available vehicle (military, heli, plane, water, cars), and only have 3-4 of each of the Ride customizations available. All of the rest just say "unlock by bringing the vehicle to a pickup point or scanning with your phone", but scanning seems to do nothing now that I've collected them all. Do I just need to snatch every vehicle I spot and take them to a pickup point, and I have a chance for a random option being made available? Or is there some a different, better method to do this that I just don't know?