I bought a Slingerland leg bracket in person at the Illinois store right before this Covid mess descended upon us. I asked about the rail mounts and was told they were no longer available. Poking around in the back room later I saw a bunch of them in a bin, but I was told they are not for sale. Maybe a direct appeal to Steve Sr. would pry one loose (I was dealing with his two boys). But the leg brackets are apparently still for sale although, like you, I could not find them listed anywhere online, which is why I made the 2 hour drive to the store.