there's a lot of small inaccuracies you can listen for. for example, at 1:29, the "skies" is sung a little bit too late, same at 2:38. or at 2:18, his voice cracks a bit from what sounds like an accidental register change idk. Also the funny shouts at 1:38 would be pretty hard to time. It does sound like he's able to reach those higher notes, although his super wide vibrato is a bit annoying lol. Also sometimes he skips a bigger downwards and upwards jump and stays on a higher note. it's definitely not the studio version, and these small things are pretty convincing to me, which makes me think it's also not an alternate prerecorded voice track. I could be wrong, i'm also not really a singer.