If the rims are riveted together instead of welded then you should fit inner tubes. You can do that fine with most tubeless tyres so long as anything that might pop the inner tube is removed (large bits of mold overrun and stickers). You need to find a tyre shop that knows about Land Rovers - maybe not so easy in the States? Until quite recently Land Rover fitted tubeless tyres to tubed rims with a tube.
I've seen plenty of people that run tubeless on tube rims but it is a risk as the bead-holder is not really designed for it.
This is what I have been told by the local tyre man - he's a well respected agricultural / Land Rover / 4x4 specialist (and charges accordingly). He says the main problem with putting tubes in tubeless tyres he's seen is fitters leaving stickers on the inside which tend to rub on the tubes and cause them to fail.
Personally I prefer tubes - last set of tubeless tyres with tubes never needed any air except when I'd deliberately let it out to get out of mud and I could let them right down to do that without losing a tyre.