There are several of them on Nirn and some people have the ability to interpret them. And seeing as they are a veritable tapestry of fate, I'd say that Tiber Septims ascent to godliness would be recorded on them somewhere.
I'm aware that the Thalmor use the ban on Talos worship as a means to weaken the empire, but seeing as the Aldmarri Dominion are probably arrogant to believe their own BS, the Elder Scrolls would cause their reasoning for the White-Gold Concordat's Talos ban to lose any and all legitimacy.
2. The Talos Shrines
As many people know, those who pay at Aedra shrines receive a 'boon' from the gods. So the mere fact that a boon is received at a Talos shrine, the same as any other shrine, is proof of Talos' status.
3. Martin Septim's ritual.
As many know, for Martin to open the gate to Mankar Camoran's paradise he required the blood of a Divine, and the blood of Tiber Septim, taken from a scraping of his old armor, worked.
4. Proof
Just as the Thalmor may claim that there is no proof that Talos is a god, they have no proof that he isn't other than a self-righteous notion that it's inconceivable for a human to be granted godhood before one of the mighty high elves.