I downloaded WiNG-MIB and I was able to locate many OIDs I was looking for, but the OID "1.3.6.1.4.1.388.50.1.3.18.1.1.4" or "1.3.6.1.4.1.388.50.1.3.34.1.1.4" should display the Area / Build information of the controller or AP does not work. I already ran a full snmpwalk and could not find any other OIDs that display the information.
The RFS6000 controller is running WiNG v5.4 with firmware 5.4.1.0-020R.