that 104 is quite a challenge !
thankfully, the Mustang is easier
coupe : http://images.gtcarlot.com/pictures/39676218.jpg
http://images.gtcarlot.com/pictures/39676226.jpg

hatch : http://images.gtcarlot.com/pictures/6444798.jpg
http://images.gtcarlot.com/pictures/6444808.jpg

Also, there was no GT coupe, they all were either hatches or convertibles ( except for 1982 when Ford re-introduced the GT but did not officially had the convertible back yet, it came for 1983 )
SVO ( 1984-1986 ) and Cobra ( 1993 ) are also hatches only

i'm not too familiar with the 1974-1978 gen so i'll have a closer look before changing anything

Similar goes for the Celica and Nissan SX as night cub suggested ( both, if i remember offered all the versions in both styles )

There is also a possiblity that most of the Celica are already classified since they had the Liftback name in extra field

Last, i won't change any that does not offer any visual difference ( big close-up of the front for example )