Are the PvP rank the same in all the different versions of wow are they different also when I play classic not mop classic I see the rank of some in there name like grunt and other ranks how they do that?
They are different. The ranks you see that correspond to the classic honor ranks are based on highest rating achieved in rbg or solo rated battlegrounds.
2400 is High Warlord/Grand Marshall, 2300 is Field Marshall/ Warlord, etc.