Inlet cam timing adjustment

Hello. Wonder if anyone can give me some advice? I have a 200, and the inlet cam timing is a little out. It was done 6 months before I bought it by a Nissan main dealer. I can't get it in the garage at the moment, and am really busy with other stuff, so I need to do the minimum...
I don't see why I shouldn't adjust the inlet timing by slackening the dephaser pulley, whilst leaving everything else in place (assuming it all looks ok)? But what concerns me is oil getting onto the clamping faces of the cam/dephaser as it's loosened. Obviously the surfaces have to be oil free to maximise the friction between them. I have never had a chance to look at the internal design of the cam/dephaser. Is there anything inside to prevent oil getting onto these surfaces, or is it essential to strip it all properly to make sure it's oil free before re-tightening?
Thanks for your help.