‘64 & ‘65 are the same sheet metal AFAIK
‘66 has the look, but not exactly as the next three years.
‘67-‘68’-‘69 AFAIK, are the same sheet metal except the ‘69’s nose.
Now there is an oddity I was made swear of and that’s glass.
Side windows are made for the year, make of the model, SO!
A ‘67 FB side glass will not fit a notch back or convertible.
They also will not fit a ‘68 or ‘69.
If someone knows better, please pipe in!
Other than marker lights, hood inserts and grill, I can’t think of any.