Mark's book is very useful, but, as he states in a small piece at the back of it, it is an introduction to Caithness rather than the magnum opus
I recommmend buying it, especially since it's not likely to be superceded in the near to medium future.
Your first label is early 1960's
The second, late 1960's - 70's.
Although only the one with pink writing is mentioned in Mark's book as 1990's - 2000's, I would expect both three and four to refer to the same period.
You are missing two labels - 1980's and 2000's.
From a piece that I have, the etched mark to the base was certainly used for a series dating from 2002 - in this case by Helen MacDonald - so I'm guessing that the etched/sandblasted mark is 2000's.