This is such a no brainer. The article states he has official records of 134 vaccinations.

They wont just keep stamping the same card endlessly until it is completely covered. How else is he going to accomplish this absurd undertaking but to have access to a bunch of official vaccination documents?

It's not outside the realm of possibility that he was also selling them, but I feel like Occam and Hanlon both agree that unless there is direct evidence, he's probably not some criminal mastermind getting rich. He's just a random person with either a fetish or something to prove.