38" or 43" seam for vinyl top
Mine had its original before I stripped it. Honestly I dont remember what width I put back on it or what it had originally. I do have some before pics that might show the seams. Its a 73 swinger.
Unless your going for a concours restoration it really makes no difference.
EDIT: Here are a couple pics. Looks like mine had the wider one originally and I put on the narrow one. Not sure, kinda hard to tell by the angle of the shot.