hey I just wanted to say THANKS to you for posting that link on serial #'s and codes , that is the most helpfull piece of information that I have seen yet on this subjectMessick's (New Holland Parts Lookup Online Catalog) says 4500 was manufactured 1/65-12/74.
The 4500 is basically a 4000 and has the numbers as a 4000.
If you are lucky there is still a readable tag on the underside of the hood, above the battery. At FORD CODES and SERIAL NUMBERS you find information on where to find numbers on other places and what they mean.