Is it possible to get actinic keratosis on an area of skin that has had little sun damage?

Yes. It is common on face, scalp and arms, but can oocur on the legs, back or. Chest. Sun is major factor but light skin color and weakened local immune system are also factors. These are treatable with cream, cryosurgery, electrosurgery.
Rarely . Sun damage is the cause of actinic keratoses but the damage may have occurred decades prior to the onset of lesions.
Actinic keratosis . Generally actinic keratoses are found on areas with chronic sun exposure such as the scalp, face, ears, neck, upper trunk, arms , back of hands , legs and top of feet.