There are a lot of date code formats that apply to specific parts or group of parts. Body part date codes are usually all numbers (see except) and do not have the year, just the month, day, shift and plant or manufacturers code (sometimes there as a letter). Body parts usually do not have a metal stamped Ford part number, and the ones that do (service parts) are mostly paper or an ink stamp. Castings usually have a year (number), month (letter) and day (number,numbers). There are so many exceptions in format and placement (even by year) that it gets tricky. Ford's vendors used different formats and that make it even worse. Try to identify the Ford part number first which has a specific format but is not always present, then locate a 3 to 5 number/letter code which may be the date code. Also be realistic, a 67 or 68 part with no 7 or 8 but a 9, 0, 1, etc in what would appear to be a date code would indicate a service part, not factory.
Jim