Not quite, they allowed NSA explicitly, and now they have their own decryption keys. Whereever did you get the idea google hid data from the nsa?
Of course executives at Google may have handed over a set of keys to the NSA after this was done. If I had to bet I would say that the NSA has more than one way to get whatever data they want from any of the top tech companies. Either via stealing, insiders or coercion they have many options.