On one level, your question is impossible to answer - by asking about prehistory, a time before records, we have no records about what people recognized or understood about their environment. We can only back into this with other means.

Ethnographic evidence indicates that people are very good about understanding their environment and are typically much more in tune with a variety of things including the movement of stars and celestial bodies than, say, someone living today in a city. They may not have understood the mechanics behind these movements, but they were fully aware of the cycles, and the relationship between the moon and the tides is easy enough to link. It is also essential since one of the first thing people "living with nature" attempt to do is to predict as much as possible - the changes of the seasons being essential, but so too the tides.

With this, it is reasonable to conclude that prehistoric people living along the coast would understand the relationship of moon and tides - even though that is merely speculation. The question could also be posed at /r/Askanthropology.