There are two sizes of cart hangers, the standard and the long.  The standard works well with 4 wheeler racks and normal thickness tailgates on side by sides, up to 2 1/2".  The long is designed for side by sides with extra thick tailgates such as the newer Polaris, up to 4" thick.
So, if you plan on using the cart with both 4 wheelers and a newer Polaris you can order a set of the other hangers than what you got with the cart.