You can also jack the whole back end up, trans in neutral brake off, front wheel chocked, spin one of the tires by hand if both rotate the same direction you have limited slip (anti spin,closed rear end) if they rotate opposite direction no limited slip(open rear end).
Either way will work one side or both (if you have floor jack).
jsimpson, if you don't have it which you probably don't because they should be able to tell by VIN.
Consider a ARB locker or there is supposed to be elecrtic locker on market, and they are putting hydraulic lockers in the Dodges for the Marines.
I have been thinking about the electric or hydraulic(if I can find some) for both front and rear in near future. I have no limited slip.
Front diff doesn't have limited slip they just have a 900 plus piece of metal sitting over the the axle. Front tires will have great traction unless going thru muck or gumbo( maybe very loose sand but you can air down for sand). You probably knew about front diff already.