Whatever it is, it looks pretty decent, if it's supposed to be 'next gen'. But it doesn't suit the GTA artstyle, so very unlikely.
More importantly though, is next gen GTA would be much cooler if all interiors were modelled too... whether that means using a lego block like system, and building up buildings with some amount of scripted variance, or if they'd have to make them painstakingly by hand, we'll have to see.