It's a cast piece, not gonna weld very well...not to mention I am guessing the piece is lost.
Not saying that cast materials can't be welded but most regular welders aren't gonna touch it. It takes a bit more prep and experience and most those guys aren't doing rinky dink repair welds on expedition side steps.
I would look for the part at a junk yard maybe? That might be your only option to get parts and pieces like that if the dealer can't get them.