That would make sense. There was a dw double with the set I got it with and the left side pedal had a hoop mount as well.Ahh! I think I know what it is. I thought those were solid rivets on the end, but it looks like they're hollow nuts? If so, I think it's a slave pedal holder for a double pedal. Pointed spurs would thread through the nuts and dig into the floor, and you'd clamp the hoop holder on the slave pedal (that would normally attach to the bass drum rim) onto the ribbed part in the middle.
It's from pedals that have basically two single pedals connected by the universal joint, so each pedal would have the full complement of spring, hoop clamp, beater holder, etc.