As at least a dozen other people have said, the fact that April 22nd is not a Sunday makes it hard to believe. Let's take a look at Pokemon release date history, shall we?:
Pokemon Red/Blue - September 30, 1998 - Wednesday
Pokemon Yellow - October 25, 1999 - Monday
Pokemon Gold/Silver - October 15, 2000 = Sunday
Pokemon Crystal - July 29, 2001 = Sunday
Pokemon Ruby/Sapphire - March 17, 2003 = Monday
Pokemon FireRed/LeafGreen - September 7, 2004 = Tuesday
Pokemon Emerald - May 1, 2005 = Sunday
Pokemon Diamond/Pearl - April 22, 2007 = Sunday
Pokemon Platinum - March 22, 2009 = Sunday
Pokemon HeartGold/SoulSilver - March 14, 2010 = Sunday
(ps I did this all without a calendar. yay me)
Looking at this trend, I only see four games that were not released on Sunday, none of which are recent. (and two of them are Gen I at that) Even then, none of these listed have even been released on a Friday, which further discredits the idea of April 22nd. GameStop also isn't exactly reliable, looking at its past history. (Hmm, was HGSS released on April 1st? Methinks not)
March 2nd also isn't very believeable because it's on a Wednesday. Again, refer to the Sunday release trend over the past five years. Odds are if it's not on a Sunday, it's fake. I wouldn't expect any official release dates for at least a month or two.