Darryl Pearson sent me photos of the Helena jail and courthouse.  The all metal jail is a good find.  My research on metal jails and cages has suggested that they were usually housed in a building.  However, this jail has a solid metal floor and roof.  Perhaps it could have housed prisoners on the outside.  calabooses were often placed near the courthouse.  In the picture of the old Helena courthouse in 1967, there is a small wooden building behind it.  Given the small size of the metal cage, it may have been inside of this tiny structure.