[TKCR]

It could be another make. The bolt used to anchor the hinge to the seat bottom, I have never seen a hex bolt used on a Chevy seat, even on the 67-72. And on the tracks, it’s hard to make out what’s going on there, lol. But because the 67-72 uses risers, it’s obvious that is why the wood was used. But it’s hard to tell what actual tracks were used.
Here’s a another picture of those tracks. They are marked 68-69, but they are 67-68. The other tracks 69 up to 72 are very similar to these, just slight variations in the mounting to the seat bottom frame and height.