Yeah, I love how everyone at the time was like "omg this piece is crazy hard, we must transpose it up to easier key to make it non-lethal!!1" Says something about the common level of technique at the time, as does the fact that when Beethoven had the right hand playing part of the accompaniment and the melody simultaneously in the slow movement of the Pathetique Sonata it was something that had never been done before...I have to almost be glad that people like Czerny and Liszt came along to raise the bar.
Anyways rk, it's unfortunate that the sheet music has been misleading, because playing it in G major would be like playing Beethoven's 5th in C-sharp minor - it would be a totally different piece. Learn it in G flat at all costs.