I've been to several closing performances. Since Sunday is a short limited run, there's a good chance it will be a regular performance, possibly with a speech at the end.
But I have been to the over-enthusiastic audience ones as well, with several mid-show standing ovations. The energy level of the actors is very high, and they can be very entertaining performances, but they are not really the best representations of the piece. But I doubt that the final performance of Sunday will be like that.