I can tell you they're lying purely because they're calling it a 2017 model. That's number one. Number two is that their rumors have not been confirmed, let alone mentioned, anywhere else, and we read EVERYTHING. Now, have similar rumors been discussed? Yes, but not what your dealer is telling you. For example:
According to this dealer there will be 2017's, but they have no order/ delivery dates.
There may be 2017 models, but they will be JKs. The next model year vehicle begins showing up around this time on dealer lots (I got my 2015 on August 22, 2014). Your dealer telling you the 2017 model is getting a total redesign makes them wrong.
And the only 2017 changes they have been notified about at this time, is the windshield will be a fixed rollbar,
This is almost certain, so this is valid, but again, not for a 2017 model vehicle. This change occurs on the 2018MY, debuting in 2017. However, they haven't been "notified."
there will be no interior rollbar,
So when the entire roof comes off, it's going to be without a roll cage? This one doesn't make sense and has not been heard before.
no cloth tops,
Something like this. The rumor is that there will be no more folding top, but it will be replaced by removable soft top panels. What they're made out of is undetermined.
and the fenders will be aluminum.
Again, something along these lines. There may/probably will be aluminum panels or pieces on the vehicle, but no confirmation of what pieces. I don't see much bang for buck with the fenders, but every pound counts. I see doors and tailgate being the aluminum pieces.