I have two and they are both the same. Both came from Guillot. Keep in mind that tea roses can vary widely in color depending on climate, soil conditions, etc. It is always possible a vendor will mislabel a rose, but I think not in this case. It is of course completely possible that the vendor has labeled this as Isabelle Nabonnand when it is not. It is however what Guillot is selling as Isabelle Nabonnand.

This is not Isabelle Nabonnand, but possibly Mme Nabonnand.