Whether it is or isn't, is broadly academic. This whole furore has but one purpose and that is to pave the way for the complete destruction of our football club. For Bayern and the rest of the little piggies, a massive fine, a transfer ban or even a temporary exclusion from the CL for a year or two, will not suffice. What they want is a situation where City are banned from European competition for decade, prevented from having any UAE sponsors or investment, and forced to sell the star players that we can then no longer afford to pay.
The 'revelations' are just mud-slinging to tarnish our reputation in the court of public opinion and whip up the appetite for that exclusion. UEFA's lot then will be to either try and enforce the G14's wishes, or watch the formation of a European Super League (which will not include us in any way, shape or form) take place outside their jurisdiction. UEFA are in an invidious position because they know that going to war with the Sheikh's lawyers might then completely cripple them financially and bring into sharp relief the corrupt nature of its FFP flagship (Annex XI, the subsequent revoking of the investment rules to suit AC Milan, the lot).
Regardless of the rights and wrongs, personally I'm finding it difficult to see this ending well for either City or UEFA. The people we're up against are our enemies, and they've always been our enemies and they always will be our enemies. The ultimate aim of Bayern's mates at Der Spiegel is not a settlement that is either legal or illegal, just to create an environment for action