Early Sketches of Lamborghini Estoque four-door Concept Leaked?

Lamborghini will unveil the Estoque four-door concept a the Paris Motor Show that begins in just a few days. We have so far been treated to three official teaser shots of the model which were kindly rendered together to show a complete shot of the rear, but it has still left a huge gaping hole in a speculation closet.

Fortunately, this closet door may well have been left ajar just a little too much after this single image, which cannot be verified as official, surfaced on the internet. Some similarities can be spotted when compared with the official teaser images, however, there are also striking differences such as the exhaust pipe configuation. If these sketches are in fact official, it is likely they are from an early development stage, and we can expect the design to have some major differences when it is unveiled.