Yeah, not sure what's the go with these rails. The bolt holes in my floor are the same disatance etc as the 69 I measured, but the rails were different between the two cars, mine being 4 inches longer (at the rear I think).
The seats I have are the ones with the lap sash through the slot in the seat so I think they are right for the year.
If I can't improvise I'll just get new rails! I think a few people have had a chop at this car. ;-)
:x