Yes, it's the same software for all variations of the same platform and generation. Generically it's typically called TA900e. The only difference between the TA908e and TA924e, etc. is the number of analog ports on the device. The same firmware will work on any of them.
If you accidentally load firmware for an incompatible unit (for example Gen. 2 firmware on a Gen. 3 device) you'll get a warning that it is not compatible on the GUI. If you have enough flash memory to hold two images it's best to keep your existing working image configured as a secondary boot in case something goes wrong.
