No, it is not. 16 is the legal age of consent between partners up to the age of 21yrs old.
there are cases of 16yr old girls that are involved with older men 30-40+ but for some unknown reason the Police and Court system seem reluctant to pursue these individuals. It would appear that in most cases, it has been accepted.... or better yet denied by general public that these types or relationships exist.
But to answer your question, No. It is illegal to use 16yr olds in anything related to Porn.