4 kits, not 3.
The most recent Revell Germany 04890 "Piper PA-18 with Bushwheels" has the big engine, bigger prop, late-style cowl, civilian-style windows rendered into the fuselage, interior and clear parts, late wings with dual wing tanks and flaps, as well as both standard wheels and the oversize Bush Wheels.
The first Revell Germany 04208 "PA-18 Super Cub" kit has the early engine, cowl, prop, L-18C military windows, and early wings without flaps and only one fuel tank.
The Revell USA 85-5483 "Piper PA-18 Super Cub" kit retains all of the initial release's parts, and includes decals to render the civilian-style windows (although, the clear parts do not fit flush with the fuselage sides, thus rendering the included window decals ineffective).
The Revell Germany 04698 "Piper PA-18-150 Float Plane" kit includes the same late/civilian parts as the "Bushwheels" kit, but includes only floats (kit does not include wheeled landing gear parts).