I wonder if it was an experiment due to some dissatisfaction that they couldn't get the white printing on black dials anywhere near as fine as the black printing on the silver/white dials. It doesn't seem all pervasive - plenty of the dark-dialled watches of the period still have the white printing - but it does seem to have been tried on a number of watches, from these 45 Datos to 2447s and Dato 12s too. They seem to have reverted to white by the second execution watches, though to my eye the printing quality still leaves something to be desired in comparison to the black on silver, including in both panda variants. By the time of the 1153 they had nailed it, but the first gen watches produced alongside still had variable printing in comparison.
Eric, to my knowledge the launch Ss had the silver starburst dials and the off-white ones belong to a later period. Some of the early ones have oxidised and aren't as shiny but the starburst should still be at least a little evident.