Playing Mk1 Warmachine

So to play against Hordes on Monday night I have to play Mk1 rules again. It has been a while since I have played the old rules and I wonder how much of Mk2 will bleed over accidentally. I am going to try and get Gravus painted by Monday so I can use him. He seems pretty cool and it would be nice to have used him Mk1 at least one time.