The CCT has a gasket itself, which could be leaking. It's common to remove the right side cover when installing a CCT so you can release the pre-compressed CCT upon installation. That gasket often comes off in one piece and is not replaced, but is also seldom a leak location. Some techs will remove the valve cover to do a CCT install, which is not unreasonable, but the valve cover gasket is a pain in the butt to get in correctly and easy to crimp/pinch during installation of the valve cover. Odds are good that your oil leak is from the valve cover gasket if you can't see obvious leakage from the right side cover over the clutch, etc. The CCT is also on the right side of the engine, and just visible, so also something you should be able to trace fluid back to, if it were the origin.