Did Toralei even get a rerelease? I don't believe she did. which is why she's so valuable to collectors. She may have been in two assortments but they'd have been the same year, thinking back I don't recall seeing her more than the once.
I'd assume the buyer knows what the date means and just reply saying "it says Mattel blah blah bah 2011" and let them make their call based on that.