"I believe the bolts used to mount the door hinges to the body
are the same. "
I don't believe they are......and '65 and '66 also used different size Door hinge Bolts between the two years. '66's actually used smaller diameter bolts than '65's did. A fact that most don't know.
Melbourne, FL (Formerly from Long Island, NY!)
1965 Mustang Convertible 200cid I6, 3spd Manual (Soon to be swapped for a '65 Date Coded C4!)
1966 Mustang Sprint 200 Registry Owner/Moderator
1966 Mustang Sprint 200 Convertible 200cid I6, C4 Auto
2007 Mustang V6 Convertible w/ Pony Package
Getting Ready for the 2020 Melbourne, FL MCA Nationals!