I have an old Decca-badged Japanese ukulele purchased as a souvinir by my parents 45 years on a Hawaii vacation. Despite the souvenir-grade quality of it, I believe it to be solid mahogany. Anyway, I went to go switch out the original fishing line strings with something better and noticed that the bridge has no holes, just slots and then a groove in back and below. This will be my first time changing ukulele strings. Should I just knot the strings in back?