Patrick, I would suggest rereading this thread, particularly the following - a picture would help (2 links have instructions).
Need help identifying Sears Minnesota treadle sewing machine
Need help identifying Sears Minnesota treadle sewing machine
Need help identifying Sears Minnesota treadle sewing machine
The location of the serial number could be a number of places as indicated at
Minnesota New Model A Serial Number
Janey - Neat people never make the exciting discoveries I do.