I spent some time riding this morning, and the low seat is growing on me. My first impressions were from sitting on the bike in the garage. After riding a bit, I noticed I can manage the bike better at stops. The padding on the standard seat, coupled with my need to occasionally reach the ground, always had me sliding forward. Not the most comfortable place to be jammed up, if you know what I mean. The low seat is more flat in profile from front to back. Less risk of me singing soprano in a quick stop. It is definitely a keeper for me.
Now that I know what gubbins are (
), I can tell you there are no bits removable from the bottom of either seat. The plastic shell appears to be identical, so the only opportunity to reshape is modification to the padding. The center, stitched panel is more narrow, so it is probably a more professional modification than I would have performed by tearing into the seat myself.
If they charged you for the low seat, you should be allowed to collect both. Then you can give both a try.