Libya Scott #29 Wmk Variety

Hi,
Scott only lists one WMK for early Libya, a crown, and I was wondering if anyone had run across this one, or if anyone has a Sassone that shows another watermark.

The stamp, Libya #29:


This is the stamp with a view from my Signoscope. The WMK looks like double-lined capital letters "N" and "Z" sideways on the left side (actual right side of the stamp), and it sure isn't a crown:


If anyone has a Sassone, or if there is an Italy/colonies specialist on the Board, can you tell me anything about this variety?

Thanks much!! Ray

Guess thus far.
The stamp has a margin location, and is showing
the text on the margin of the Wmk forme.

Often seen on Crown agents postage stamps.