Not necessarily. I never change my opening times. Mine is always set to 7:45 AM, even through daylight savings changes, regardless of when the sun comes up. Keeps the birds a wee bit quieter in the morning by having them stay in the coop, and my flock is used to that schedule so they don't fuss about not being let out earlier than that.
Obviously if you have pecking order/crowding issues, or live in an area where high heat is a concern, that won't work, so you'd have to adjust to compensate for sunrise.