Yes they do, I only saw those Aussy LCAs after making mine but I think that is the way Chrysler should have made them in the first place.
If you look at the very first picture I posted in this thread you see a difference in thickness on the stamped plate where the crack began (probably due to the manufacturing process of stamping them), so I think it had to crack there anyway, which is the weakest point and does not allow reinforcement by welding a plate all around.
Anyway, after welding the reinforcement plate these arms feel really solid. The aussy LCAs also have the sway bar tabs in the same position as the ones in Brazil, in USA the sway bar tabs are more in the middle of the arms, guess they were sending overseas all the old stuff they did not use in USA any more.