Do the systems that support sending gameid to BlueRetro require an internal installation?

[Koohiisan]

Or will it work somehow just being plugged in to the controller ports on those systems externally? Specifically interested in GameCube, but I read in another discussion that Krikzz's ED64 might also do gameid. Would that need to be internal too? Just wondering how the gameid gets to the device, I suppose.