Hi,
There is one thing regarding LabVIEW OPC Server capability, it is going to expose all the data internal to labview to the external world in the OPC format.
If you are using the Allen-Bradley FlexLogix Processor, you will still need a Allen-Bradley OPC server,or some kind of driver that behaves as a OPC server. If you have the data in the OPC format, then you will be able to read the data from LabVIEW.
You should check with Allen-Bradley if they have a OPC Server for that especific PLC model.
Best Regards
Andre Oliveira