One must remember the feather and hammer drop on the last Apollo mission. I'll grant freely that faking this stuff, now, using current tech, is quite possible. However I can guarantee you, as a photgrapher and student of film, that thirty years ago such fakery was flatly impossible. If these shots are not genuine, it would have taken much more money than NASA put into the Apollo missions at the time to fake them so completely. No, for a couple of reasons.
Dust is very small and takes a long time to accumulate.
Enough to be visible on a single Moon rock could take millions of years to collect, assuming an otherwise static environment. The Lunar surface has never been static. Again with the talcum. Put a small rock on a table and sprinkle talcum over it, then rap heavily on the table's surface to simulate a small meteor impact. A lot of the talcum falls off the rock and pools around it.