Yep. High grimoire equal PVE skill for the most part and experience because you had to go through all of the year 1 content to get it. PVP skill on the other hand is another story. You can only get a limited amount of grimoire points in PVP, so there's that. 4600 is a fairly good amount of points for a pve focused player. 4800+ probably means he's grinded pvp too.