help needed with 904

So getting things cleaned up here and I'm not liking the top pressure plate. It seems to be depressed more in the center than on the outer edges? Not warped but I'm not sure if it's supposed to be that way and like not reversible? I know everyone's going to kill me for throwing that back in there a but I'm not spending more money! Okay so now I'm about to clean up the last five parts and put the new seals in and restock everything period I better start soaking the clutches. I'm assuming the drum that has the snap ring I can leave alone because I don't believe there's any more seals under there? This is where you speak up or hold your peace LOL okay back to cleaning those parts and then I'll check if I got any answers if not I'm just going to go for it. Oh yeah and that checkpoint check ball that I'm pointing at what's that all about? I'm leaving it in there just cleaning it up.
20170502_124542.jpg