The starburst hot stamp design was created by Paul-Son as a cancellation stamp. The company has had a long-standing internal policy of not allowing blank chips to leave the factory, and the stamp was also used as a way to identify (otherwise blank) chips sold in their stores.
They also offered cancellation services to companies for chips they had produced, plus they applied cancellation stamps on produced chips that were unsold (usually either error chips, or unsold due to non-payment) so that the chips could later be sold publicly to recover costs (typically in their stores located in Las Vegas and Atlantic City).