You gotta be more specific. What are the parameters? Do we know exactly what day the Pyramids were finished? Of course not. The month? Nope. The year? Definitely not. The decade? Sorta. The century? Pretty certain.

So does not knowing the exact year mean "we really don't know"? Because that's really inconsequential. Narrowing the build date to a time frame of a decade or two seems pretty accurate to most historians considering the time period.

Most claims about the ¨mystery¨of the pyramids see them as these odd structures comletely out of context. This is patently wrong. Most pyramids have an associated mortuary temple, or even full-fledged complex. Take a look at the full layout of Djsoers step pyramid at Saqqara. We know its from Djoser because it´s in the highlight of a complex entirely dedicated to the pharaoh, with his name written on every other solid surface. This is true of most other pyramids.