Not sure the "official" time, but the directional sinage on property had MK as Full just before noon when we were out by Port Orleans.
As far as I know the complete capacity closing was not for very long. MK was open for guests for most of the day. Hubby went into work at 3:45 and said it was really busy but had died off and that after fireworks it was/is very slow (would be a great night to utilize EMH).