Just some clarification,
It was used. I don't mean the text that's actually displayed ingame. If you caught the exact same pokemon with the exact same data in HG and SS, the part of their data that contains information on what game they are from will be different. The game checks them and is programmed to show Faraway place for both.
There was exactly 2 kinds of unused game origin data in DPt reserved for HG and SS.