Savage, I believe sausage dials are filled, for the historic models (some of the Contemporary dials are just "painted" on the surface of the dial, I think). They just fill them to the point that the lume is above the surface level of the dial. Some of the older "sausage" dials are filled to at, or just below the surface of the dial. My 002D is just like this 118, filled to just below the surface of the dial. I'm sure your gen Zero (and I believe ALL gen Zeros and 005s) are filled to levels above the surface of the dial, right?
FWIW, there doesn't seem to be a standard, I've seen pics of the PAM040 (which was a B series watch) with lume filled just below the surface, and with lume that is filled well above the surface of the dial.
I'm afraid this might be yet another example of Panerai's legendary inconsistency.