I don't think it's impossible that ML had a pair of replacement panels in stock with serial numbers that date earlier than than those of the speakers you're looking at. Unless, ML has some sort of Q/A requirement to pull stock that reaches a certain age.
Perhaps ring up ML and ask them to confirm that a pair of Aerius replacement panels matching those serial numbers were sold sometime just prior to 2008 ?
Have you heard the speakers being offered for sale? Do they sound good? If you haven't heard them and proven to yourself that they are acceptable, I would start looking somewhere else.
Good luck
BTW, I was "this close" to being in Pisa earlier this month. Lovely city!