Using IGS (Industrial Gateway Server) with a PLC3

I have an iFIX system to upgrade that has and SLC504 and PLC3 on DH+. The current system uses an ABR driver and RSLinx with a KTX card. We have to get rid of the KTX and would like to use an ethernet gateway to DH+. RSLinx configures fine with the gateway, and I have been able to bench test comms to an SLC 5/04 over (Ethernet to DH+) and it seems to work fine (The IGS is using the Allen-Bradley Ethernet driver with the gateway IP and the SLC DH+ station address). I don't have a PLC3 to test with before attempting to startup in plant. Does anyone know if the IGS set up with Allen-Bradley ethernet (PLC5 family) will work with a PLC3? Difference in I/O addressing being I0:2/0 vs I:0/2, etc. Any help or suggestions would be appreciated. If the IGS and gateway will not work, could I use the AB USB to DH+ converter and just keep the ABR driver in iFIX intact? Thanks