I saw one of these machines in a Bridgeport wharehouse in Staten Island New York. This was back in about 1986. In my entire Bridgeport career since 1982, this is the only one I have seen.
I would be curious to know what kind of drives and motors it has!
It was released after the R2E4. The R2E3 and R2E4 were not 100% reliable. I believe the R2G4 was an attempt to please the public by offering a machine with a Fanuc control (thus more reliable).