The first digit 5 is the model year = 1965, second digit T is assembly plant = Metuchen, 3rd and 4th digit 07 = coupe, fifth digit T is engine size = 200 CID I6; and 6th thru 11th digits represents the Ford car number built that year at that plant starting with 100001.
Just came back from looking the car over. It does have a few small rust spots than the person mentioned and will need some body work. Not right now, but will need it. Plus whomever painted the stang could have done a little better job. The interior looked good, even though you could tell it had been worked on.
Considering the car is 40 years old it's def worth the 4 grand that it looks like it will be going for. Unfort not for me, as my wife and I both agreed even though were not looking for a "show car", it was best to pass on, looking at the future body work that it will need in time.