@roadhog2001-0 you are disregarding the previous statement, which is the only statement that matters.
Any person that appear in any depiction of actual sexually explicit conduct were over the age of 18 at the time of production, and all records are kept, as required by law.
The subsequent statement indicates that the website might contain media that is exempt from this specific law (record keeping) because it doesn't contain sexually explicit conduct, or because they were produced prior to the existence of the law, when record keeping was not required.
To put it shortly, they are not required to keep age records for content that is not actual sexually explicit conduct, like nudity or simulated sex, and lastly, content that were filmed prior to the law.
The reason for this disclaimer is, one might request age records for a specific production, and they don't have it, not because it is illegal, but because said production is exempt from record keeping for one or another reason.