Many years ago, in the Aircraft Mechanics training/apprenticeship programs, a carry-around toolbox was a sheetmetal skills project, that would be useful in later years on the job. The boxes would be constructed as the different skills were learned; layout, setback, specific radiius for different gauge sheet, dimpling or countersinking where appropriate, and proper setting of the rivets themselves. Another aspect was economic, efficient use of the raw materials. You were given enough material to build it, but you had to figure out how to do it with what you had. A great skill when you are working for a company.
At the testing stage for certification as an A&E (now A&P) you were required to show practical hands-on knowledge of your skills. These projects were a way of showing that, without laboriously performing the task in front of the examiner.
I have a small collection of Aircraft maintenance training texts from the '30's & '40's, and I have seen some examples (& drawings) similar to the posted toolbox in them. I'll try to scan a pic or two. No fancy raised stampings, however.