Anyway, back on topic... I think that PD will not let Lambos slip away this time... they will probably have the newer ones like the Gallardo, Murcie, etc. Think about it... Audi owns Lambo. Audis are in ght GT series... what's to stop Lambo? But that still doesn't explain why they weren't in GT4... hmm...
That same theory was used during GT4 about Fiat & Ferrari.
When it comes to licensing, the head manufacturer does not have any say. Fiat, Ford, GM, Volkswagen, etc. They all may own (or did own) Ferrari, Aston, Pontiac, & Lamborghini, but that does not mean they controlled everything under them. These manufacturers have the right to say who can & can't use their image, cars, etc. VAG & Fiat do not have any say, & more than likely, do not care to begin with.
The only time you'll see the owners stepping in is when the company owned starts building something the head manufacturer does not like. As an example, with Porsche now controlling Bugatti, it has been rumored that Porsche is limiting Bugatti's development of a faster car because Porsche is supposedly building something just as fast. But, lately, Bugatti doesn't seem to care.
It takes something big for Fiat & VAG to step in and say no. Licensing is not one of those things they have interest in. They leave that & nearly everything else up the manufacturers. In short, finances, scandals, & similar-products are really the only things that catch the owners' attentions.