You don't need the same dish in your RV that you have in your home but the dish you describe will not work with the Genie (this receiver requires DirecTV SWM technology) without adding some additional hardware. This is not expensive, just different. You can find the info you need that will allow you to update that antenna to SWM here, http://www.winegard.com/kbase/upload/2452242.pdf or, my recommendation, you can use one of the current DirecTV SWM antennas without the hassle of the additional hardware. The rest of the setup is the same as the old setup you suggest but without additional hardware or issues.
What I post is my 2 cents and nothing more. Please don't read anything into my post that's not there. If you disagree, that's OK.
Can't we all just get along?