Can anyone identify this bucket seat?

I traded a guy a pair of 69 Dart buckets seats for what he said were a pair of 71 Demon seats, sight-unseen. Now I have these seats, and they don't look like any Demon seats I've ever seen. The closest I can come by browsing the Legendary catalog is a 71 or 72 Plymouth B Body seat. It looks like that seat, but with fewer seams across the seat and up the back. Does anyone know what this seat came out of, for certain?

I compared the tracks on these seats to a set of tracks I have on a 68 Barracuda bucket. The stud spacing from front to rear appears to be the same, but the spacing from left to right is a couple of inches wider than the 68 seat. Can anyone confirm for me that the 67-69 A Body bucket seats used the same "pattern" for mounting in the floor as the 70-72 A Bodies?

What will it take to make these work in a 70 Swinger? I don't care too much about originality, I guess. Can I just swap the tracks to A Body tracks, or is it not that simple? Should I just get my 69 seats back, and look for a different pair of seats?

Let me know what you guys think. Thanks.