67 Dart buckets are exactly the same structurally. They have different upholstery pattern, of course, and they also have a chrome medallion with a Dodge logo between your shoulder blades, which I found uncomfortable. The seat backs changed in 68, so I don't know if there is any other precise match. Of course, any A-body bucket from 67 on would bolt in, but if you want low-back with no headrest you are looking at 67-68, or early 69.