It's funny, looking at your Lang, yours was rusted in the exact opposite way mine is now. I still have a nice black front, but my fire box is rusting. I have tried a couple of different paints, but that box gets so darn hot, it is hard to keep paint on it. As far as your fire box, that plate looks a lot better thank the stock unit that mine came with. The set up mine has has warped because I use a weed burner to light my logs. I have the grill mounted on the front of my Lang, but i mostly use it to store wood. I bet that basket in front takes a LOT of weight off of the unit.
Very nice looking restore! Make sure to update this with post with pics.