Not unusual to have hairline cracks in the gelcoat on corners and around screw holes on these older models. These look a little more substantial than hairline cracks. I would do a little deeper investigation to see if they are deeper than gelcoat. If it is only gelcoat then its no big deal and only cosmetic. Fix them if you want.... or not. If it is a crack in the fiberglass then that would be a deal breaker for me.