Just in case anyone is curious-
I talked to Gus at Van's and he said that the F-303E part designation is not applicable for the 7 or 9, as this sheet of .063 was first for the RV-3 Part F-303E. Gus said that this sheet of .063 comes with both the 7 and 9 kit, and it is in both the tip-up and the slider kits.
He was not able to off hand know where this sheet was used, so I will look back in the finishing kit drawings and see if I can't find where it might be used.
Ron