1. Mauduit was a sergeant of 2nd Battalion of the 1st Grenadiers of the Guard and he published his Les derniers jours de la Grande armée in 1847-1848.
2. Christiani was in command of the 2nd Grenadiers in 1815 and he wrote 'Ce fut M. Golzio, chef du 2e bataillon du régiment, que j'ai chargé de cette mission.' in a private letter in 1835.
3. Pigeard used sources from S.H.A.T Xab 68 à 74 for his Waterloo OOB, he confirmed Golzio was in command of the 2nd battalion of the 2nd Grenadiers.

So I choose to believe Christiani and Pigeard.

And, if you double-check other things in Mauduit's book, you may take his words with a grain of salt too.