3 point seat belts

Latches were added to the hinged seat backs with the shoulder belts in 1968. Without those latches the seat back goes forward with you in a collision. The belt across your chest would hurt more? The crash test dummy knows.
Your 67 has the coat hook right above where the 2 side glasses meet. 68 and later has the shoulder belt anchor there. Coat hooks moved rearward about 3 inches. That coat hook sits on a wedge shaped bump out in the roof metal structure. Remove that bump out to put a belt anchor there, forfeit the cook hooks. There is a recent thread where the shoulder belt is anchored just below the quarter glass. Only install like this I have ever seen ( i should have saved that picture ). I dont think the metal there is strong enough for a belt anchor. Would have to lift the belt up and over your shoulder too. The only good point about that install was not having to get past the headliner to add a anchor.