Push 'em Toy box

Found this in someone's trash (gasp!) and thought it was super cute. It was covered in kids stickers so I cleaned it all up with some goo gone.  There is "some" rust  - however I would think that would be expected.

I wanted to get some information on it as I have been online all day and can not find any comparables.  All I can find is licensed ones from the 50s - Mickey, Disney, Raggedy Ann - however those were made of pressed cardboard and this one is all metal, which would date it earlier than the rest, I would think. Any ideas? I would really appreciate some help

This one is missing the casters.