Interesting question. Some devices prefix a "2nd." or "3rd." if multiple cards are detected (resulting in 2nd.scsi.device), but I think GVP just adds unit numbers (so the first device on the second card will be unit 100 instead of 0). I don't remember exactly how it works.
Fortunately, the version command has a UNIT keyword that might help. (type "version ?" to get the command template).
If you can't get the shell to cooperate, just boot up without the SCSI/RAM card and run "version gvpscsi.device" again.