A hole is an opening on both sides of an object, through which water could travel. An indentation is similar, but appears only on one side of the object. Without an equivalent opening on the other side, there is no pathway for water to travel through. With the groundwork of these definitions laid, are you referring to an indentation? If so, find something else to worry about. The manufacturing process for plastic parts can change, and so can the appearance of the parts, even though they still are functional in older equipment.