The most commonly used gauge is 'light gauge' 45-105, if the bass is new I would almost guarantee that is the gauge.
Do you really need to change them? A lot of bass players leave them on for longer than a few months, and sometimes years, depending on the tone you like. New strings are too bright for some, and prefer them well broken in.
D'Addario XL's, JB-EXL170BT (Balanced Tension), are good because the string tension, and volume, is more even across the strings. The gauge is 45-107, slightly heavier 4th than std light gauge.