As suspect as it is, it doesn't necessarily prove the moonlanding was a hoax. To quote one analyst, Paolo Attivissimo:
"This may be a misunderstanding caused by two Dutch artists, Liesbeth Bik and Jos van der Pol, who organized an artistic event in 2006. This is where this “moon rock” first appeared. The event was very tongue-in-cheek, so maybe they concocted a fake "rock” and plaque to test the perceptions and knowledge of the participants, and then the origin of the rock was forgotten. There are quite a few clues pointing in this direction.
For example, why would the plaque of a US gift have such very Dutch mistakes as “Apollo-11″ (with a hyphen) and “Centre” (British spelling)? Why would the US government give a moon rock to a Dutch politician who at the time had not been in office for over 10 years? Why give away a fist-sized moon rock barely three months after the first sample return and before Apollo 12 landed? Why was the rock shown for the first time in an art exhibition rather than a science exhibition?