Can you help me identify this headlight assembly?

I have this vintage headlight assembly, probably from the 1930's, and it looks like it might have been on a truck, due to its heavy/sturdy mounting bracket. The housing measures 10 inches across the front, and 6 inches deep.Any ideas what it might have come from? TIA.

Al

 

Big truck manufacturers usually outsourced parts like headlight assemblies, so the same headlights by suppliers such as Guide (a subsidiary of General Motors) and BLC could be found on many different makes of big trucks, buses, fire engines, etc.