This specimen continues the blurring of the distinction between the All Steel and Langdon product lines.
The key differences between this specimen and the 1950 version are: the type of steel plate used for the back, the glued-on paper label, and the stamped foot brackets.
With the exception of the back plate and two piece construction, it would appear that all of the moving parts are otherwise identical to those used on the Langdon Acme of this same approximate vintage.
A Langdon Mitre Box Reference 