uneven chain tightness

[unfazed]

No, the only thing that is likely to will fall out is a load of crud which is thrown off by the chain and is stuck inside the cover.

Cover is only to protect us from the rotating bits and the operating mechanism for the clutch.

Any oil in there is from the lubrication used for the chain unless there is an oil leak from the sprocket seal, the clutch pushrod seal or a broken crankcase  :lol