Y/YY = Year of manufacture (Single digit for some 1997 and earlier models).F/FF = Factory code (No factory designator for some 1993 and earlier models).NOTE: Pre 1994 productions also frequently omitted factory letter codes and appeared as all numbers. In 2008 models begin to appear without a factory i.d. 1.5.3 F-Serial used on LP Std'59/'60 models and Tribute/Plus models.
