Is there such a thing as a GM n soundfont? I would suggest that any soundfont is at least somewhat dependant on the specific equipment that you wish to load it on. For example, there may well be a GM 2 soundfont for Windows, or for certain DAWs, or for anything else that loads soft fonts, and certain devices may be able to use the data designed to certain general standards.
Maybe, you question should include a reference to the particular device, or system, that you wish to load it into. Also, a search for "<device x> GM 2 soundfont" may be more useful?
Geoff