How, you may ask, is the Gelgoog from the Gqx AU a Gelgoog? Clearly, it is designed after the GM from the UC timeline, so why is it called a Gelgoog? You see, Zeon's Gelgoog project in the UC timeline started for the same reason as the failed Gouf project, and the successful Dom project: to make a mass production MS more capable than the Zaku. The main thing, though, that separates the GQX AU and the UC timeline is that Char Aznable discovered a prototype Gundam and stole it. While stealing the Gundam, He also found prototype GMs Guntanks and Guncannons. Zeon, through this mission, obtained blueprints for these MS, and found that the GM was exactly what they wanted to make with the Gelgoog: a mass production MS more capable than the Zaku. So the design they used for the Gelgoog project was the stolen Federation GM.