It has never been clear who holds the rights to various F1 cars, there are some discrepancies about who owns what and when with several different parties owning the rights to all kinds of things.
So anyone talking with any authority on this subject is generally talking rubbish, as so proven when GT5 came out with the Ferrari F10 after everyone who talked about this subject at the time was adamant there was no a way current car could be included because of Codemasters license.
It's been shown a while back that the right to F1 racing are owned by the FOM, thus simulating it is also owned by the FOM. Individual cars is another matter. Not sure why people wouldn't know or haven't read to see at least some determinate things.
Generally speaking I get the impression the cars themselves are the property of the teams or team's owners and so they are able to license the cars directly from them.
But it gets a bit muddy when you're talking about featuring an entire grid of cars from a single season and calling it an "F1 World Championship". The rights to "F1" and "Formula 1" belong to FOM who generally license it out to one developer/publisher such as currently with Codemasters.
So you do indeed know, just like many f1 fanatics that have researched and read up on it, and I recall seeing an article about it a while back when CM got the exclusive right to do so.
So to answer the question, sure why not, the evidence out there suggests anything is possible bar licensing the entire 2013 grid. And as mentioned, the Ayrton Senna tie up would be a bit flat if they literally have 0 F1 cars that Senna drove. Seeing the lack of an MP4-4 (probably the most famous and obvious car to choose) in both Forza and F1 2013 makes you wonder. (yes I know the Senna license is to 87 but whats to stop them licensing the McLaren seperately?)
I don't see why they couldn't have the Lotus and Toleman, since the team that formed and runs now owns both if I remember correctly. I'm probably wrong on the Toleman part. That would need some researching to see if true, just because a team bought an old team doesn't give them the trademark rights to said old team, so I think I should research that before I jump the gun.
However, that doesn't mean they can't get it since from what PD said, they have the ability up to 1987 after that Senna's image can't be used for some reason. This is where major speculation comes into play. I agree though that if PD do this they need at least a couple of his cars I wouldn't mind one of his Toleman and the Camel Lotus.
The confirmed F1 cars licensed by Polyphony so far are the Team Lotus cars on the Goodwood sculpture:
Lotus 32B
Lotus 49B
Lotus 72E
Lotus 79
Lotus 99T
The Lotus F1 E20 wasn't present on the GT6 in-game sculpture so Polyphony haven't got the license for it, with Forza having the E21, maybe Turn 10 have got the Lotus F1 cars exclusive to their game outside of the official F1 game?
First off do you have anything that proves PD has obtained the license, if so I think we'd all like to see it. It's quite big to have such cars and them not directly tell us, since this is one of the biggest harps. It would also help PD be able to put themselves forth against up coming sim competition to have the 49 and 32 since others already do.
As for FM, they don't have the E21, they have the E20. I doubt they're exclusive as well since Ardius just got done explaining that multiple games have same manufactures at one time. The only exclusive rights I've read and heard about are those the FOM hold over a field of cars being simulated and called "F1" racing.