There are different schools of thought when it comes to this and I thought I'd put it to the group. I've heard people say that if peel ply is used there is no need to key the area up before laminating/painting/glueing. I've also heard the opposite that even if you have peel plyed once the laminate is no longer 'green' use must key up before adhering to it. 

Keying up is a lot quicker on a peel ply finish as half the roughness is already there so there is no harm in further keying to ensure the finish is even. 

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant