the DeltaF508 5T is a description of only one gene - a person must have two CF genes in order to have CF. If they have only identified one gene so far and are still looking then your child may end up only being a carrier with only one gene, or if they find the 2nd one, they will diagnose as CF.
On occasion people with only one gene but clear cut CF symptoms and issues do get treated as if they have CF, assuming that the 2nd gene has not been identified yet, but might get identified at a later date.