The view that every event, which occurs, can be included in some universal law is called determinism. The truth, or not, of determinism has been discussed for centuries with different results. The best and most important thing for a researcher is to not consider laws as infallible truth, which cannot be modified. Archaeologists should definitely use statistical laws without pretending to produce universal laws that in any case would be limited. This does not interfere with the consideration of archaeology as a science.
Science uses laws.
Which laws depends on the subject. The fact that archaeologists can use scientific laws is a proof that archaeology is also a science. Any statement in archaeology, like laws but not only, needs to be confirmed. Once confirmation is interpreted as a relation between statements, it is time to use logic. Logic allows to reach a confirmation saying that the truth of some statement can guarantee the truth of others.