Here is another Wellington printing, perf 14, of the 6 d kiwi with enough marginal space on the left to show what looks to me like a plate marking.
Stanley Gibbons 1907 6d Pink Wmk single line NZ and star
Guaged 14 Type 48
"Stamps of Type 48 have a SMALL DOT
as described in note after 417a"
"The above new plates have a minute dot between the stamps in the horizontal row, but is frequently cut out by the perforations."
Bib: Stanley Gibbons Brit. Commonwealth Stamp Cat. 1974