Update:
For my 2004, I had the universal dually flaps. If you look at duraflap.com it is the style #10L (style # 10 is shorter for 2WD trucks). They will fit on the newer trucks, you just have to drill the holes. The main difference, and the reason I'm going to get the model-specific, drill-less flaps for my 2010, is because there's not a lot of structural mounting surface in the new trucks due to the design of the fenders. On the older trucks, essentially you had a SRW bed with a big fender bolted on. So, how I mounted my flaps was a row of bolts to the outside of the fender, and then halfway in there was a row of bolts attached to the bed portion of the fender.
On the new trucks you don't have that part of the bed behind the wheel well liner, so I like the fact that for the new trucks, the mounting portion of the flap is taller, meaning it comes up higher and catches that third bolt on the fender flare. It also mounts with one or two bolts on the inside, to the liner.
I got an email from Duraflap, and they attached two pdf files. I attached one of them, but the other one is too large to put on here, and I'm trying to figure out how to break it down so I can post it. It has better pics of the install than what I can find on their site.
SOLER