You mean the bracket to the seat is different? The Buckets bolted to my floor with no issue.
Sorry, I'm not always very clear when I rattle things off like that. Please allow me to elaborate. The bench seats utilize 2 brackets: they mount to the floor using only the outboard floor mounts. The split bench uses those outside mounts as well as the inboard mounts for a total of 4. The bucket seat brackets use these same 4 floor mounts. The floor mounts are all the same.
The difference is absolutely in the bracket design- and the difference you're looking at is that a vertical piece makes a 90° bend, with bucket/bench brackets bending in opposite directions from what I recall (it's been a while). No amount of swapping positions will make things work. However, you can elongate the bolt holes in the brackets and then loosely mount things together. The bolts will go in but won't be happy, you tighten them and the brackets pull into place. Or you can weld on some new mounting tabs that are simply cut down washers purchased from a farm and implement store and things go in smoothly.
The mounting holes in the bottom of GM bucket seats are all the same from the '70s until '04 so you can swap almost any GM bucket seat to your G Body bucket brackets. By extension, you can mount nearly any GM bucket seat to G Body split bench brackets with a little modification.
I have not yet tried to swap power split bench bases to bucket seats but had assumed the split bench bases were all the same, the only difference being the power option. Bonnewagon states above that his manual bucket seats bolted directly to the power split bench bases, which confuses me. That would indicate that G body power split bench and manual/power buckets share a base design whereas the full bench and manual split bench are different.