HELP! Dart sport seats

[74Dart360]

I recently started a project 74 dart sport. Well I have gotten to the point of the interior after 6 yrs of hard labor and countless paychecks. So the lady that I took my seats too called me today after having them for 3 weeks and she said that the seat cover I bought from legendary won't fit the seats! Personally I think she half assed the attempt but my question is would it be possible to put foams from a 70-71 duster/dart sport on my seat frames that I was told were from a 75? Please any advie would be greatly appreciated