is this a real 599 SA?

Sure it looks legitimate - SA Aperta. 1 of 80 though a few extra may have been built by Ferrari...

 

140+ known cars is hardly a few more...
If one takes into account, that there are some typical collector markets without a SA Aperta sighting to date, that number is likely getting higher in the future!

 

140 cars is something to talk about but the extra cars has not hurt Ferrari in any noticeable way. These cars still sell for over list price so the extra cars has not financially harmed the original buyers whose car is still worth more than they paid for it.
Also Ferrari continues to sell all the Limited Edition models they care to offer for sale.

 

Why don't they say it's a limited production of 140 cars.. it wouldn't change its value, but they wouldn't lose their credibility.. Sometimes I just think they're making a fool out of its customers..

 

When the program started they thought 80 cars would be sufficient. Obviously other customers pressured Ferrari to build them a car as well.
When the F40 was introduced they said maybe we can sell 250.
Then the Americans came along and wanted a version they could register in the USA. Over three years they build more than 200 cars just for the USA. Eventually they built more than 1000 cars in total.
With Ferrari they can be flexible regarding the numbers built...