`67 GM A body shoulder harness clips

[VintageMusclecar]

Would anyone happen to know where the mounting holes for the shoulder harness clips (<u>not</u> the harness anchor points) are supposed to be located on a `67 A body? I have shoulder belts installed in the Chevelle, but I haven't been able to figure out the correct location for the clips that hold the belts up against the headliner when they aren't in use. (I've already tried to peek under the edge of the headliner, but it's securely glued in place along the edges and I really ain't too keen on the idea of ripping it just to get a look underneath)

Any help would be greatly appreciated.
Eric