I should add that the fit is about as good as it gets, meaning there is not slop between the two locating (blue) bars.
I tend to lean on the side of the tech guys from Trenton Farm Equipment. My recall LS dealer, in FL.
The link should be there to lessen stress on the nuts & bolts connections below.
I told a peek under the blue painted diamond plate floor & noticed on heck of a thick mounting plate in position for the connection point above the plate.
Your floor plate appears to be also cut out as mine is. Just your BH isn't offering our connection point.
Strange, to see this step NOT removed from the factory assembly (plate cut out).
I would have to look deeper in better day light but you may be able to weld in those two missing anchor bars for the link connection.
If it comes to this, we'll be glad to make measurements & forward them to you.
On a better note: we removed our stump yesterday & wife sent it down in the woods to decay away. Now for the crater fill in.