I just wanted to share this information because I saw it talked about but never confirmed.
An RS232 Gen 2 Printer CAN be converted to Netplex and Vice Versa. The jumpers by the molex power connector determine the protocol. If the jumpers leave the two open pins to the front of the printer, it is set to Netplex Protocol and if the open pins are to the back it is RS232.
See the attached picture. It depicts the jumpers configured to RS232. If both the jumpers were moved back one position, it would be Netplex.
Of course the firmware still needs to be flashed.
Some Williams machines use RS232 printers configured for RS232 but flashed with Netplex firmware. Those jumpers can just be swapped to let them work on IGT machines. I just did this to mine.