I agree, the other replies you've received are correct.
Figured I should mention, the brass harmonica read-board you found is an uncommon version, made to allow you to play the harmonica during both exhaling and inhaling. A harmonica made to play only during exhaling into it has reeds on only one side of its reed-board. Note that yours has reeds (the long narrow thin brass strip riveted onto the end of each slot) on BOTH sides of the reed-board.