The only way to find out for sure is to dig him up, open the casket, and have him checked by a forensic specialist with no interest or stock in Padre Pio, ideally, one who’s never heard of him.
One can speculate endlessly or wait until General Judgement Day. Then we’ll all know!
A wise person doesn’t believe everything or even most of what is on the internet. By now, it has been inflated by the RSP/FM’s.