As it came up in another thread why do you think there is an engine cover? Looks? Purpose? PITA?
I think they are PITA and tend to be just more parts to make sure I have all the bolts for. My wife still has her's because she likes it original, and I have lost one of the bolts. But I'd probably have thrown it in storage if the car was mine. And the only reason of that the general public thinks they "need" them.