Would VECTOR have replaced that or edited it ?
No, it would have placed a very small .BGL in one of its folders (sorry, I don't know exactly where, I don't use OrbX ), which contained only the altitude correction, and GSX won't use this, since it's not a complete airport, and GSX only use a single .BGL at a time.
Check if you have something for that airport under Scenery\World\Scenery in the simulator own folder.