Vintage Dalbey's Omaha Special Valve Oil Bottle - Flag on bottom? - Rare

Description

Vintage Dalbey's Omaha Special Valve Oil Bottle - Very old and Rare
Approximately 3.5 inches tall
Please view the photos to see the condition of this item. It is empty and missing the bottle top, but it appears to be in good shape. I can't read the bottom of the bottle, but it looks like it has a flag in addition to some numbers. I could find only one photo of this on the internet on a collector's webpage, but there were no details.
This is part of my 90-year-old father's estate. He was a mechanic for Eastern Airlines, and he was also in the Air Force. He loved collecting all types of antiques, including automotive, oil/gas, airline items, and MANY other types of collectibles.
If you are interested in his other items, please see the other items that I have posted. I will be adding more things from his estate almost daily. Please feel free to ask if you have questions. Though I don't have expertise in most of them, I'm happy to answer what I can!
Thanks for your interest!