I was window-shopping on eBay, and found horns for sale manufactured by “Thomas”. The model is T-158, and they appear to be electronic. However, the grille and body style are EXACTLY the same as the elusive 4048.
That is a very great find! Awesome job on getting it!
From what I’m seeing online, Thomas was a division of Benjamin who made the 4030. I guess this was the successor to that horn.
And then succeeding this horn was the 4040!