Balthasar van der Ast has been most productive with flower still lifes, but the ones featuring sinistral snails on them are few. Even fewer are those where sinistrality seems to be problematic, as the shell shown might not be so in nature.
This case of “Still Life of Flowers in a Glass Vase”, an oil on copper now in the collection of the Museum of Fine Arts, Houston, is such a case. The whitish shell is clearly sinistral and belongs to an (unidentifiable) European species. This leaves the possibility that Van der Ast has made several studies before he made this painting, and perhaps combined an empty whitish shell with a study of a snail seen from the left. The painting was made in 1624.
However, in my search for cases to test the Gould hypothesis this one stands out as one of the exceptions.
 FAH, inv. BF 2007.4. http://www.mfah.org/art/detail/still-life-flowers-glass-vase/. Sarah Campell Blaffer Foundation.