Yeah. It's no big deal. In fact, if your Zelda cart was one of the first batch released, it won't even have security screws. My Zelda cart has five little flathead screws, as opposed to the later three inverse torx screws.
Anyway, even if you DO have the little star shaped screws, just buy a gamebit from an electronics supply store (or any number of places online) and no more problem. From there, it's just a simple matter of replacing the battery. Some just have a simple spring clip holding the battery in place and for contact, others have it soldered to the contact.