Yes, green anoles can be brown. They turn to blend in with their surroundings although the change is no where near what chameleons can do of course. They'll be brown most of the time in fact and usually are only bright green during mating season.
It looks like a common anole to me - sometimes the toes get very long like you see here. They are not native to Washington although California is a distinct possibility - it could've somehow hitched a ride up north, lol. Most likely it escaped from someone's home and made its way into your dad's store. Are you going to keep it? They are easy to care for - just make sure that its diet does not consist only of crickets. Those have too much exoskeleton and they need more soft-bodied insects. They are neat little lizards.
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