Hay Jaz Your probably right about there being 2 different mounts, I have 2 Sets of spare Vented Disk Calipers, both of them are identical except their mounting holes are different (Slightly further apart) , and they have different Model numbers on them
But their is probably another toyota model out there that uses Sprinter Pads. I will do some reaserch later tonight.
I only Use Standard Disks front and rear on my rally car with upgraded Pads and it stops on a dime.