If you are considered a baritone singer, then your vocal range would supposedly be from G2 to G4 but most baritones in pop music use their head voices and go much higher than this. When they say a baritone has a vocal range G2-G4 do they mean that G4 is the highest note that can be sung or do they mean the highest "chest voice" note that can be sung?
(possible bad english, i'm italian) They mean the highest CHEST VOICE note that can be sung. However vocal classification doesn't rely only on vocal range, for example I know some really talented guys that are tenors but can also sing as low as me (and I'm a low baritone), however their voice is more comfortable in the higher range and this is what makes them tenors. The same concept can be applied for baritones, one friend of mine is a baritone but can sing a B4 in chest voice, it's just really belted and not comfortable at all for him, his comfortable range is much lower than B4 so he's a baritone.
Vocal classification ranges are just a guide but not everyone falls exactly in those ranges. I'm a low baritone and my vocal range in chest is E ♭ 2-F#4, sometimes G4, but with mixed voice I reach F#5 and with falsetto I go up to C6 easily.