As cibernet said, you have to use "export" command, mostly I use "export file filename", if you do that, MT place a file in the disk with the complete configuration, so you could download it entering via FTP to the RB. (I think this way is more secure than copy an paste the exported configuration commands)
Then, in the confiuration output file you have to edit (or delete) the mac address of the wireless interface. (search were said "/interface wireless") So, when you "paste" that configuration to another RB with another SR2 cards, you avoid any kaind of problems with wireless interfaces macs.
I hope to have helped