I think the part of the number codes '11 12 20' refers to the casting date. I have restored two Kohler tubs with the last number in the sequence being '14' and '15' from residences in Richland Center, Wisconsin that I know were built/upgraded around the 1917 - 1920 time frame. But, I have found a definite reference for this yet.
kohler
The very first bathtub was invented in the year of 1883. It was invented by an American inventor named John Michael Kohler.
John Michael Kohler invented the first enameled bathtub when he enameled a cast iron horse trough in 1883.
In 1883 he enamelled a cast iron horse trough, so yes, he invented the enamel bathtub.
John Michael Kohler did when he enameled a cast iron horse trough in 1883.
John Michael Kohler invented the first enameled bathtub when he enameled a cast iron horse trough in 1883.
In 1883 John Michael Kohler enamelled a cast iron horse trough, but people had been bathing in wooden and metal tubs for years before that.
Some of the most famous bathtub or shower brands are: 1. Kohler 2. Moen 3. Triton 4. Lowes 5. Alsons 6. Culligans 7. Aquascape Designs 8. Barclay 9. Ana Bath
Rob Kohler goes by Kohler Bear.
The address of the Kohler Public Library is: 333 Upper Rd., Kohler, 53044 1545
Rob Kohler's birth name is Robert Kohler.
Matt Kohler's birth name is Matthew Robert Kohler.