The recognition guide is great for this question. The differences between 64.5 and 65 is quite alot.
The front nose of the early cars is subtly different, and the hoods are different. The horns are different, the early cars have generators instead of alternaters, and this includes a different dash light (gen vs alt) the 64.5 had only coupes and convertables. 65 was the start of the fastback... The early cars had different power steering and disc brakes to the later cars I think too. Some engine codes changed between the years too.
Many many differences, but no real advantage or disadvantage as far as value goes. Its worth whatever you are willing to pay for it.