I am sure that you saw the shiny Meowth also. Those towers were the thing i really liked about FireRed and LeafGreen. I have a desire to go there, even thou i have no Pokemon (being traded to Emerald, then Diamond, finally Platinum - HG/SS.
It appears that A LOT of people saw shiny rocks - Geodudes including me on Mt.Ember. However that foolish one self destructed on the first turn.:frown:
My first was a Zigzagoon from Sapphire in front of the day care.
Edit: Legit Shiny - Mewtwo from LG.