[Hutch]

Fleetbeds come in long and short and the fenderwells are on the inside of the bed.
Stepbeds also come in long or short and the fender wells are on the outside of the bed along with the steps.
Some folks call them Fleetsides and Stepsides or Short wide beds or long wide beds
Also long narrow beds or short narrow beds

You bed length depends on you chassis length

Not sure about what you get in a kit