Either is possible, but Kay's records are hard copy, handwritten in Gallifreyan, and mine are heavily encrypted and under a security block of my own programming. So to alter the records a person or groups of persons would have to have the ability to access to our personal space, forge hundreds of pages of Kay's handwriting in Gallifreyan and hack through the finest computer security the most technologically advanced race in the universe can offer. [Narvin is not big on modesty.] Not to mention whatever other skills would be required to alter others' records. And accomplish it all within a few days.

It's not impossible, but mass alteration of memories is easier. A strong enough telepathic field could do it. [He's not going to mention that for a while he thought that he might have been behind something like that and was blocking the memories from himself.]

A third possibility is that the records are from one universe, and are accurate to that universe, and we are from another. That somehow we and our alternate selves were switched. And Adam exists in our universe but not the one the records are from.