1995 C280
 

I am planning on replacing the upper timing chain cover gasket on a friends car. Is there a timing guide pin that I have to pull to do this job or just two bolts and remove the cover? And do I have to remove the valve cover? Sorry for all the ?s. Thanks.

Yes there are pins that need to be pulled for chain guide rails. You can easily break a rail reinstalling the pins, so be careful. Yes the valve cover needs to be removed, it's a beeyatch to reinstall, as there are 6 seperate "donuts" for the plugs.
Be careful what you select for the metal to metal surfaces. I recommend Loctite 5900.
Gilly

I was hoping that it was going to be easy, now I dont want to do it. But she has a bad oil leak.

Do you think I should get a new valve cover gasket or can I use the old one?

I think you should get a new one, yes. No reason to take it all apart then cut corners on something like that. Oh you also have o-rings for the coolant stub pipe that need to be replaced at the same time. It's not all that hard to do this job but not all that easy, either. Not a good job to pick if it's your first Mercedes to work on.
Gilly