If PFBC told me they sampled 3 reaches on Bob's Creek and captured 45 brook trout, I wouldn't question it or be surprised by it.
If someone said they caught 45 brook trout on Bob's Creek in a day, I would be skeptical of the veracity of the claim, but I wouldn't be surprised if it were true.
Neither of those conditions says anything about the number of brook trout relative to brown trout today, or how that composition might have changed over the past 30 years. Nor does either of those conditions speak to what may have been a cause IF there was a decline in brook trout and an increase in brown trout.