Not much reference in the Scott about New Zealand varieties, especially KGV. Here is a NZ Sc #176 (perf 14x14 1/2) w/o watermark (or I couldn't find one). This particular stamp is way over inked at the top. Is this a one off or is there a plate variety that Scott doesn't recognize?
And just for what it's worth, there isn't mention of color variations in Scott either. Here's a picture of four different Sc #176's.