Without a photo I can't tell you exactly ... it may be a solid stem with a removable washer on the end ... or it may have a containment nut on top of a plastic body that simply pulls out once the containment nut is removed
http://plumbing.about.com/od/fixture...t-Repair_4.htm
That link has about 8 pages of photos that may give you an idea of what it takes. My 3150 has a single handle with a cartridge so I can't compare. There's nothing different about an RV faucet compared to your house ... just cheaper made. If there is a nut under the handle, it should be right hand thread. If it is just a one piece stem with a washer on the end ... upon reassembly first make sure you turn the stem as if to open it all the way so you won't mess the washer up tightening it back into the faucet base.