As far as reproducing an accurate body, it doesn't matter if they are pre-assembled or a kit. I mean, you aren't going to make a carbon fiber frame or anything. However, it would be best to get something with doors, hood & trunk that open so you could reproduce the door jams, etc. With the Pocher model, you get lots of useful detail like the inner hood, etc. Also, the larger the model, typically, the better the detail will be.
I'm sure all officially licensed products get their source files from Lamborghini.
I agree that Pocher looks like the sweet spot if one were going to take this route. If there is nothing better available in a few years, I will probably do just that. A combination of spalshed OEM panels and scans for this model would probably work out perfect. You just have to make sure you upscale perfectly so it all matches up.