Gors Kallman piano serial number reference information. Here goes some pictures of it: What do you guys think? Do you find this post useful? The name on it is: Gors & Kallmann - Kaiserl. So, for this, I decided to search and know really what value this piano really have. I never thought it could cost something like this. Some other day, a fellow that works with antiquities offered $6,000 for the piano. Guys, there's an old piano that just sticks around my grandma's house but it's not being used anymore. Judith, I have a Gors and Kallmann upright piano, serial number 45943 Made in Australia.