Looking at your pic, which to be honest I really didn't do before, I doubt it's a late 80s bike. You'd have aero brake levers and indexed shifters. I can't see the shifters but I doubt they're the early Campy Syncros (not necessarily a good thing even if they are).

In the 70s the Mirage was indeed second from the bottom but they played alot with the names into the 80s and it might, or might not, be higher in the lineup. I agree that MotoLite tubing means low.

Paint scheme with the contrasting headtube looks earlier Mirage to me.

Regarding the Campy, Chorus has always been good. Some of the other 80s groups such as Victory and Triomphe are not so well regarded.

Get a good look at the bike and negotiate. The guy picked it up, kept the (probably) upgraded pedals and now wants to make a few $. You should be able to haggle.