From Bulbapedia, the community-driven Pokémon encyclopedia.
In some pre-release material the medals were shown to shine with stars on the corners. However, in the final version there is no such star, instead it is just a line going diagonally over the medals.
| A pre-release picture of the medal box
In the coding of the games there is an alternate colored sprite for several Pokéstar Studios opponents, which are presumably Shiny sprites. However, it isn't possible to encounter the Shiny sprites in the final version of the game.
| The shiny colored F-00
|| The shiny colored F-00 2