Hello, I realize this thread is rather old but wanted to ask for some help. I just purchased a Minnesota treadle foot but I cannot find a serial number and it does not have a letter- just Minnesota. It is in a parlor cabinet that has spindles on the top. The swingarm supports have the words: Pat March 27, 1900, on both of them. It has a box of attachments and a few bobbins and 2 shuttles. I guess I am looking for help in finding a serial number (if it matters) and to find out if the few manuals online for the "A" machine would still apply to my machine. I have the machine serviced by a professional and he said it just needed a cleaning and oiling, he didn't charge me for it because he said he had never seen a Minnesota machine and was impressed with it.