They are, but keep in mind that the side marker lights differ between years -round in 68, rectangular in 69 (the 67s, though,didn't have any).
Yes, they fit, but you will have to use the respective year grilles as the head light positions are different, with the 69 headlights higher and further towards the grille center than the 67/68 fenders.
68
68 is greater than 67.
The factors of 67 are: 1, 67 The factors of 68 are: 1, 2, 4, 17, 34, 68
67
The 67-9 Barracuda Fastback have the same glass. The difference is the 67 used a gasket/ seal which utilized a (chromed) plastic lock strip. In 68-9 the gasket was different. It was self locking and used a stainless steel reveal molding.The 67 gasket and lock strip was problematic as the lock strip shrunk and the corner moldings would fall out and leave gaps. 67 gaskets are hard to find as they were one year only.Many people with 67's convert to the 68-9 self locking gasket w/reveal moldings as these gaskets are readily available. However the stainless steel reveal moldings are not being reproduced at this time and are becoming harder to find.All the above information is also correct for the coupe (notchback).
68
Yes
67 Camero has a vent window. 68 Camero's do not.
68
65.8
Yes it will the trim clips are made different in 1968 my understanding is you have to add them after you measure a 68 for spacing and use a 68 seal and trim but the window glass is supposed to be identical. I had researched this because I have a 67 notchback coupe that needs a replacement window.