I really don't know what to make of this one, but here are the choices:
a. The US never wanted to give a moon rock to the Dutch so they gave them a fake hoping they will never notice.
b. There is wood on the moon.
c. No moon landing ever happened, ergo no moon rocks. ( I know I'm going to get emails on this one).
d. Packaging error.
Occam's Razor says that I should pick the simplest one, so (b) it is!!!!