Yes, if Mars had no atmosphere, its surface would likely be covered by dust and sand. Mars is known for its dusty and barren landscape, and much of the surface is composed of fine particles of dust and sand. The Martian atmosphere is thin compared to Earth's, but it still plays a role in shaping the planet's surface.
The atmosphere on Mars helps to suspend dust particles and create dust storms, which can transport and redistribute dust across the planet. The lack of a substantial atmosphere, as on Earth, means there would be no weathering or erosion processes caused by wind, and the dust and sand particles would settle and accumulate on the surface over time.
Without an atmosphere, the surface of Mars would be more susceptible to the direct effects of radiation and impacts from space debris, which could also contribute to the formation of a dusty and rocky landscape.