I have a 103 pc set of Trianon flatware by International Silver Co. While I know the mark is International Silver-there is also a small “C” stamped on the back on the Forks (up by the beginning of the tines.) What is the significance of the letter? Some of the spoons have a “B” and the knives, and the salad forks do not seem to have it at all. I am just curious as to what those letters mean? Is one letter more favorable than another? And does NOT having one of the letters decrease value?