Pretty weak form of identification. Would be much more certain if the body had something Prigozhin is known to have rather than the body lacking something Prigozhin is known to lack.
Still, I think we all kinda knew he was dead the moment he was like "Actually instead of instigating a civil war in Russia I'm going to take this very generous deal they offered me where my treachery sees almost no repercussions whatsoever."
Honestly, he probably wasn't dead at that moment. He could have been fine if he could have shut the fuck up. He'd likely be watched and essentially on house arrest for the rest of his life, but he could have lived. Anyway, good riddance. He was an evil bastard. Hopefully we get to say goodbye to Putin sometime soon too.
Everyone should be aware that the final say is provided by Putin. And is a foregone conclusion - for purely tactical and propaganda reasons, the official version will be that Prigozhin is dead. And nobody will contest that - least of all Prigozhin himself.
It's not like it would be completely unheard of to lose a finger after being in a small jet that got hit by a missile that then hurtled 30k ft to the ground and exploded.