How may I identify the firmware in use on my 3D printer?
Send M115 to the printer. This command is 


  Request the Firmware Version and Capabilities of the current microcontroller.


Response example:


  ok PROTOCOL_VERSION:0.1 FIRMWARE_NAME:FiveD FIRMWARE_URL:http%3A//reprap.org MACHINE_TYPE:Mendel EXTRUDER_COUNT:1


For more info see here, RepRapWiki- G-code - M115: Get Firmware Version and Capabilities.



Of course, this isn't guaranteed to tell the truth, just whatever your generic clone firmware had in its source code.