Well LPS is released from gram negative bacteria, and was never designed to be a toxin, it just triggers an immune response in T cells, which then activate a systemic immune response, including fever via IL-1. So most likely no, they do not act directly on the hypothalamus.
Don't think of everything that causes a fever as a pyrogen, IL-1 is a pyrogen, LPS is a endotoxin that can result in fevers due to activation of IL-1