Does anyone know the casting code for a 1954 Chevrolet truck 3-speed transmission?

The casting code might be different from 1953 and earlier, but there were only minor changes in 1954.

Another way to ask this question is: does anyone know how to ID a 1954 truck 3-speed (enclosed drive-shaft) from earlier 3-speeds?

Here is minimal information on the ID for a 1954 Muncie 3 speed transmission

Thanks,