What is the difference between AIR-AP1231G-A-K9 and AIR-AP1231G-E-K9.Thank you,

I am in the process of adding the g radio upgrade kit, AIR-MP21G-A-K9 to an older Aironet 1200 b radio. Does the g upgrade kit support the AIR-ANT1728 antenna? I currently have two AIR-ANT4941 antennas on the b radio and would like to boost my Airo...