Accessing Variables Assigned To Prefabs

Ok, I'm currently making a checkers game in Unity and I have managed to get the board and piece made and in their correct positions. The Checkers itself has a Class called 'Piece' and this is where they are Instantiated and variables assigned.

I want to be able to select those checker pieces and access the variables that are allocated to that single piece. I can select the piece through raycast and finding that gameobject through a tag. However, I have variables such as 'isKing' which I would like to access and I am struggling with this.

All Help will be appreciated muchly.

     //Instantiates the prefabs of the checker pieces
     public void DrawPiece(Vector3 _checkPos, Color _color, int _checkID, bool _isPlayer)
     {
         //Once Drawn set all initial varaibles
         SetPiece (_checkID, _checkPos, _isPlayer);

         //Draw and set the Player Checker
         selectedChecker = (GameObject)Instantiate(checker, _checkPos, Quaternion.identity);

^^ this is within the Piece class, and the 'SetPiece' just assigns the variables to that prefab.