I'm sure @untopo can post progress pictures from when he was building it, and the fact the model is available to download at a certain russian site is pure coincidence
I can't say I know for sure whether or not this model is using some of the GTS model, but it seems a whole sidepod of the car is just mirrored from the other side, when it is completely asymmetrical on the actual car. The engine intake is missing, fuel filler was ignored, and going off of the assumption that they just mirrored the other sidepod over, the exhaust vent in between would be missing as well.
This angle as well shows another fault that was not missed on the GTS model, but the nose has more curvature to it in real life, as compared to what's shown on this model.
There's a few things here and there that are missing, like the rear wing endplate not having the same 'kick' outwards as it does in real life, but since it is a work in progress, these can all be changed before the final product is available. While there is some suspicion of it being ripped due to the lack in WIP pics, I'm led to believe this is his own work.