The DCU01 is a universal drop ceiling mounting bracket for the AP3825. You can find information for it in the Installation Guide for the AP3825.
The WALL02 is a mounting bracket for the AP380X that allows you to install the AP on a J-box. I don't think that we ever updated the documentation; it is a low runner that was made for a few specific deployments. I can get dig up some pictures if you need it.