Yes, GenStone can be installed over Stucco! Deck screws are what we typically recommend when installing the faux stone however, if it is tough to get them into the stucco, similar to applying to a concrete substrate, you can opt to use Tapcon screws. In either case, we do recommend using Tyvek paper on the substrate and a polyurethane safe adhesive (PL200 or PL300).
The Tyvek paper, in this case, would protect the stucco from the adhesive should you, or any other person ever wants to remove the stone. Below is a link to our "how to install" guides, which explains the different processes necessary for the various substrates and a variety of materials.