Ok thanks for fast reply, I know for the marti report availability so that what i mean "without help of it" I ll check under the headliner , i hope ill see something that help me cause the quarter has been changed so for now the car is a summer daily driver but i want to make a rotisserie resto most concours correct that i can with that i have and next time i ll tell the plant and date of my car
Really appreciate the forum 
Both quarter panels were changed? Is it possible the quarter panels were changed high enough to cover these holes over? Have you be begun the restoration and stripped the paint off and located where and how the quarter panels have been replaced?
I am no expert on the 66 Mustang per say, but what I see in your pictures do not clearly indicate one way or the other but in my opinion, (and it is only an opinion) the holes I see inside under the headliner seem to indicate the car used to have a vinyl roof. Also (in my opinion)
if the quarters were changed higher than those holes, the holes were covered over with the new quarter panels since I see metal behind the holes. To the contrary, if evidence suggests the quarter panels were replaced BELOW these holes, then I would think the car did not come with the vinyl top. I believe the answer is in stripping down the exterior finishes and locating all previous work. Just an opinion based on your images.
Richard
