April 16th, 2015, 12:36
Sometime during its life the A2A Mustang was updated and the model remapped. The "old" textures only work with the "old" model and the "new" textures (the ones with more bitmaps) only work with the "new" model.
Not sure there is any way around that.
Hope that helps a little. Someone will be along to give a more complete answer soon I'm sure.