Let's try this.
In an effort to track and identify parts Ford, contractors and sub contractors placed markings on many of the parts that make up our cars. Many of these markings included the date the part was made. This also allowed Ford to identify lots and time periods if there was a problem or a recall of certain parts was needed
The dates might be cast into the part ( for cast iron, aluminum and sometimes plastic parts) , stamped into it ( common on stamped steel parts) or applied in other ways as they did on glass windows. Another method was a simple ink stamp (alternators and some grills come to mind.
When someone used the term "numbers matching"{ it can mean a number of very different levels and one (especially if someone was purchasing a car) should always ask for the other persons definition of "numbers match"
Kind of like the terms, restored, concours, like original, rebuilt ..... LOTS of different meanings
For some, numbers matching only means that the car has all of its original VIN's in the original locations and that if the IN calls for a 289 as original the car has a 289. For others it might mean that the engine and transmission have VIN's that match the car or just the date codes on those parts are from before the car was assembled. For some matching numbers can mean that the car has all of its original VIN's in their correct location (including engine and trans if it was built during the appropriate periods or model) EVERY part on the car that has a date is from the time period appropriate for the particular car.
Unfortunately there is not one (IMHO there should be
definition of the term and it is often used very freely in advertisements and at auctions. So confirm what the person is stating and confirm if it is so
Sorry for the loooooonnnnnng response
