Hello josep_vito,
I am not a licensing expert (I support Anti-Piracy technology, not Licensing) but the way I understand it, if you or your oginization has a current MSDNAA subscription and you are using the software within the Licensing Terms of the MSDNAA Subscription, then yes, that software would be Genuine regardless of it not having a "COA Sticker". In essence, the MSDNAA Subscription paperwork is the COA for the whole subscription.
If you have any additional question regarding your MSDNAA subscription, please see
http://msdn.microsoft.com/en-us/academic/default.aspxThank you,
Darin MS