Strictly speaking, a video can be non-hardcore and still R18, provided it was given a certificate before the guidelines were changed in 2000. If it's R18 and certificated now, it's hardcore. So if the stock you're buying looks old, ask.
I think that the film 'The Pornographer' had a spunk on the face of a woman cut out of the 18 version - possible R18 version would restore these 12 seconds.