No, he probably doesn't. The exhaust gas velocity is thousands of meters per second. The dust scoured from the surface is entrained in that flow, and so impacts the surface of the struts, footpads, etc. at tremendous velocity, with tremendous kinetic energy (at that scale). It is far more likely simply to bounce off than to somehow stick to it. Tarkus' mistaken expectation no doubt derives from assumptions that it would billow up in clouds, aerosolized as it is on Earth in an ambient atmosphere, and then settle gently back down on all the nearby surfaces.