Perhaps before the days of Unas, as we know that the writing on his walls was "transcribed" but not understood by the carvers, and so has flaws in it's transcription.
I know they have a "date" for the structure, but I am not saying it is spot on.
Beware the Adze!
Beware the land it came from.
... ... ...
That chisel of metal ~bi3 n pt~
With which he opened the mouths of the gods.