Happytrails,
:-/ If your confused, then maybe I'm confused too, but the 1998 3124 I looked at just had a plastic latch on the inside of the door to keep the two halves together while open (in use). The exterior side has a piece of aluminum angle fixed to the bottom of the top half (like yours)
If I understand your picture correctly, yours doesn't use the plastic latch, but a metal bracket to hold the two halves together. If I get a TM with the new plastic latch, I will definitely replace it with metal latch of some type, like people are discussin here.
Some other trailers I've looked at have differing designs that I might borrow from. I can't rember the name of the latch, but one one similar to old suitcase latch is popular on other doors....
