No. In female form, reese can't use magic but when she in male form, she suddenly can use it. Beside Poura said that anyone in another gender need time to get used of this body. That is why anyone in another gender side can't use magic right now.
Technically, Poura said "Once your gender is swapped", which, i take, means both ways regardless of original gender (but then again, it depends on how accurate is translation). My angle is - Poura used genderbending to "shake up" Reeze's body constitution, so she could overcome whatever was stopping her (she did have a moment in a fight against Zelphina) from using magic (and, per usual tropes, because she has "enormous amount of magic power", it wouldn't take long for it to come out).
On the other hand, if she was originally male, that would mean that Poura turned Reese female early on in her childhood (it was stated that genderbending is Poura's skill), and that either no one in the village knew or they kept silent about it.