Hi Scotty 14. I was online looking for info on an item I ran across at my homestead. My search led me to your post. I also have a Gregory Purity milk cooler manufactured by Oakes and Burger Co. Wondering if you have found out anything more in your research, and if so if you would share. The cooler I have is stamped size 4, and also has two 23" long troughs stored with it. I am from the third generation involved in my family's dairy farm, so my interest is more personal than financial. Thanks.