After watching the Michael Franklin Trevor trailer this morning, I noticed something peculiar about the cars in the background of several clips.
I noticed that there appears to be 2 different models/designs for the Buffalo. Here are some images, taken directly from the trailer using a snipping tool.
There is the possibility that the first 2 cars are the same, Side Vent and Rims(?) modified. Possibly a vehicle R* has used during a playthrough of the game's missions that has been customized.However, the 3rd image is where I question if there are 2 variants of the Buffalo in the game. The third picture clearly has taillights like GTA IV's Buffalo. Both the FIB and civilian variants had taillights like the 3rd image. It's difficult to tell but I think the first image's vehicle appears to have the GTA IV taillights. The 2nd image has taillights that resemble a new 2011 - 2013 Dodge Charger .
I understand that GTA V is still being worked on by R*, which brings up the possibility that the 1st and 3rd Buffalo's may be a "beta" vehicle and the 2nd image is it's final form to appeal to the time gap between GTA IV and GTA V.
All images are taken from the Franklin part of the trailer.