Iv just been listening to Westwood on Radio 1 here in the UK, and he had his American corospondant, 'Miss Info' on the show. She was saying that someone at Interscope had told her that Dr Dre had worked with Game, and 'ghost' produced some of the tracks in order to keep Curtis 'Interscope' Jackson happy.
Basically, 50 hated the idea of Dre going off and working entirely with Game. Remember, Dre spent more time with Game on The Documentary than he did with 50 on The Massacre, and 50 didn't like that.
To keep the peace, Dre moved Game onto Geffin records so that he was fully outta his G-Unit contract and 50 would have nothin to do with DA. Dre worked with several producers, including Pharrell and Will.I.am etc and did contribute to the album, but has not appeared in the credits. This way, 50 dont know he worked with Game and everything is cool.
Dre also advised Game not to diss G-Unit on the album (though he did on his own mixtapes) as again, this would stir it all up again.
This is only what Westwood was talking about, and he knows the rap game and the people inside out. If this didn't happen, then something else has done. The fact Game doesn't diss Dre also prooves theres no beef.