The serial number on the frame just above the battery should help you on that but it may not be there . If it has the hydraulics, it should most likely be a WS model. It has a lift control by the driver's seat for the bed.
The Utility model has extra hyd controls for accessories- and the GP model has none , I don't remember about the turf model but that it came with turf tires originally.Then there was the recreation model -camo. Different special promotions may have added features so this is just an idea of the basic models out there. Some parts will be the same anyway, it just depends on what it is.There is a very old thread on here about how you can find out the year model as well by the year # being over so many digits in the serial #. I think it was by BCZoom.
I had an '05 WS and really like it and it used no oil at over 4000 hrs when I sold it.. good luck , bordercollie