So this song just hit the internet a few hours ago and its absolutely amazing! Its actually a cover of a 2009 song from Donnie Dumphy - Cold Beer but its a phenomenal cover regardless.

Question is, can someone with an ear for music figure out what chords he is playing from the video?

So now that the roommates have woken up and I can play, it sounds like Am, C, ?, F I think. I can't figure out what the hell the third chord is though, anyone have an idea?
Ah yes, open G didn't sound right to me for some reason but playing it as a barre sounds much better. Thank you!
You should check out his song Marauder its pretty rad. Chords are the same just dif order Am-F-C-G