C5AE only tells that the casting DESIGN was for a 1965 full size Ford product. ( and were often used in other models) usually Mustangs have an C#OE part prefix that says it's a Fairlane part. Castings are often used two or three years
This may explain the additional numbers. At the bottom of the page it shows the actual date coding that tells the date part was cast.
Your second number seems to be a date code of July 26th 1965. Very late and possibly a '66 production part(?) The 7 seems odd but some parts have a "shift" number also but I don't know how to ID that.
From a concours point of view Fords don't really have "numbers matching" the way GM does. Numbers matching usually means it has the proper casting and a date code about a month or so before the car was assembled as the motor would be already built and awaiting to go in the chassis. Stu