This section is going to take some good 'ole fashioned research. We spoke to Waterloo about obtaining the history of whom they produced boxes for and during what timeframe(s). Unfortunately, their latest "acquirer" upgraded all their computer systems 4 years ago and one of the consequences of that effort was a complete purge/wipe of all their historical records.
According to Waterloo's website, the company was founded as the Waterloo Valve Spring Compressor by Nicholas Sulentic, a Croatian immigrant in 1922. The earliest reference we could locate was in a November 8, 1922 newspaper advertising for local salesmen. Until we get back to more detailed research on Waterloo, please refer to the above link to Waterloo's history page for information.
Dating a Waterloo made Tool Chest. Date codes on all Waterloo produced tool chests are located in the floor of the top tray, between the middle and front of the box, in the leftmost portion / section of the top tray.
On Waterloo produced roll cabs, the date stamp is typically found on the front face of the lower right corner of the frame.