Can the cisco 1231G autonomous become a LWAP and Join a WISM controller and be and be managed by the WCS. I tried doing the upgrade to 12.3(7)JA3 as recommended by CISCO. But there were no option to join a controller.
The 1231 is fully supported in the Autonomous to Lwapp migration :) The upgrade to 12.3(7)JA3 or 12.3(11)JA is just the first step of the process so you have a little more to do still. Here is the latest doc that I could find that details the process.
Upgrading Autonomous Cisco Aironet Access Points to Lightweight Mode
