I found these two yesterday in a collection I bought. Both have a G rotated 180 degrees and used for the number 9. One piece Bill Meier has shown in another photo has a G as the 9 in 1893 and is the "dropped AY" mold. The one I have is also the dropped AY mold. The second piece has the G being used for the 9 in No 9.
These seem to be a somewhat scarce error to find.