I recently purchased a 2016 ram 1500 crew cab they havnt yet came out with the weathertech floor liners for the 2016 does anybody know if the design has changed or will the 2015 model fit?
Yeah this is like how I had to get Bilstein 5100s for a "2014 Lone Star" from Autoanything because they didn't have the Lone Star (or Big Horn) trim listed for 2013. There is no difference; the lower control arms were changed to aluminum from steel in 2013 so 2013+ shocks will be the same. Really it wouldn't have mattered, because the part numbers are the same regardless of trim anyway but they sent me a 15% off coupon and their system wouldn't honor it online so I had to call. The point is that, like bubba said, a lot of the time aftermarket companies don't update their systems to reflect new model years, trims, and a lot of them still have our trucks listed under "Dodge".
Closer to the original topic, there have been some floor hook changes through the years that will affect fitment. My dad's 2009 Ram has 1 floor hook on the driver's side and none on the passenger side so his passenger Weathertech will slide around. My '13 has 2 floor hooks on each side, but I also have husky liners so they have the studs on the bottom that prevent them from sliding, and they have 3 spots for floor hooks, so whether you have the 1 hook or 2 hook setup they will fit.