Nope, definitely doesn't show this on the official WDW site -- at least not yet.
Does show MK's open from 8 AM-midnight 3/20-4/1. On 4/2, the MK closes at 11 PM. Only EMH mornings it shows are Fridays.
OP, do you think it's possible that the person you spoke with mixed up the fact that the MK is now going to be open an hour earlier to everyone (at 8 AM) rather than that the MK would be open an additional hour early just to on-site guests? Just a thought, and guess I'll just keep watching the official site and will check directly with WDW a day or two before departure.