I saw on YouTube brittanicca restorations that he removed the metal ring oil seal cover that (on his engine) had been attached with machine screws: mine has the original rivets holding it on. do I need to remove this cover, when I can push the oil seal in from behind and leave the cover as it is? Or is there a reason I need to push the new seal in from the front? Obviously I have removed the timing cover as part of the engine rebuild.