San Francisco Samuel Bridge School Medal - Bronze Pattern Or Trial Piece

I received this interesting item recently, it is a San Francisco Schools Samuel Bridge medal in bronze:


Samuel Bridge Medal - Bronze

The Samuel Bridge silver medals were awarded to the top male students of San Francisco grammar schools from 1879 to 1915.

A similar medal, the Denman silver medal, was awarded to the top female students from 1865 to 1915

The medals were originally struck at the US Philadelphia Mint and later at other places.

The bronze medal was not awarded to a student as only silver medals were awarded. The newspapers at the time usually listed medal awardees in articles on school graduations.

A regular Samuel Bridge silver medal:


Samuel Bridge Medal awarded to Frank O'Donnell in 1895
Silver, 34mm, 18.75gm

The man who sold the bronze medal to me told me he bought it from a coin dealer in Brookfield, Massachusetts.

The bronze medal has no year or inscribed awardee name.

My guess is that it probably was a mint trial piece or pattern.

Is there something else that it could have been?