Is my official time my gun time or my chip time?

Gun time. Under ASA Rule 33.17, awards are decided on each runner's gun time: from the gun that starts the first wave until you cross the finish line. Your net (mat-to-mat) time may be given to you as well, but it is not used for individual or team placings.

When a race uses wave or staggered starts, all potential prize winners in a category must be seeded in the same wave so they share the same start. Runners who start in a later wave are not eligible for category awards. Organisers must state this in the event rules.