Yes they were. All fastbacks had their rear windows tinted, without exception. The options for tinted glass were; windshield only ( it was actually the shaded style), or all windows which actually were tinted green and called SunRay, except as noted for the windshield. The percentage call would be a WAG at best.
65 Hi-Po F/B
67 GTA F/B (small block)
MCA 27479
65 Hi-Po F/B
67 GTA F/B (small block)
MCA 27479