Hi Friend,
Yes,as soon as an AP discovers the master first it will share it's current boot code and if it is not same, controller will update the code.
For your ref, here is the boot sequence of the AP,
1.AP requests and receives DHCP address for itself
2.AP determines IP address of Aruba controller (controller IP)
3.AP receives its image from the controller via FTP; config pushed via PAPI
4.AP creates a GRE tunnel between AP and controller
5.Client packets encapsulated in GRE (port 47) tunnel to controller
6.802.11 Frames de-capsulated and switched or routed to the network.
7.AP and controller communication via PAPI (UDP port 8211)
Please feel free for any further query on this.