Nope, thats wrong.
In that game you don't see them in battle, you see them like they would appear in your party page,
(Where it shows all six, of those little guys ) And the sprites like that, look the same shiny or non shiny, and that doesn't count as the shiny encounter rate.
I know this, because I have legitamently caught a Shiny Entei in Silver Version.
And I've legit ( No event ) gotten a shiny Suicune in HG ( Through lots of resets ).