This post is just because I found this old thread confusing.
I also have an Atwood six gallon electronic ignition water heater. On my unit, and on the new Dinosaur UIB-S boards as of 2015, there is no extra adapter needed as described above. It's just plug and play, working with the existing wiring. You want to buy the UIB-S board, and the matching two-tab mounting kit, which comes with a waterproof cover for your new board.
1999 27' Safari + 2011 Mercedes GL 350 Turbo-diesel