I wouldn't bother with the receivers but I'd leave the existing dish in place. If it's a good dish, properly mounted, aimed, and all the wiring in place getting DirecTV service would be a very easy "plug and play" with new receivers. If not then it's a pretty simple install to potentially swap out the dish, etc. Again, since there's a good chance the receivers aren't owned if current models then I'd let them go. If they're not current models you probably don't want them anyhow especially if you have HDTV's and want to get the most out of your TV's.