Nothing to add to what Stefano said: the ship was surely painted in overall Grigio cenerino chiaro, which was a very light grey, looking almost white in some photos.
To get a general reference about RM destroyers from the beginning 'till the end:
- 1880 - 1900: the very first destroyers were painted in a very dark olive green, similar to the Olive drab used on US vehicles
- WWI: most destroyers were painted in overall dark grey with white ID letters; some were painted in light grey with black or red ID letters.
- This state of anarchy lasted until Fascism got a firmer grip on the Regia Marina; from circa 1926 onward all new constructions were painted in overall light grey; from 1930 it was virtually impossible to see a RM ship in dark grey, as the new regulation, stating that all military ships had to be painted in Grigio cenerino chiaro, was adopted. ID letters were brick red.
- WWII: at the end of 1940 no destroyer had yet received a camouflage scheme; at the end of 1941, it was hard to find one still in the prewar measure. All this without true regulation as each scheme was specifically designed for an individual ship. Most of the schemes however relied on three colours: grigio cenerino chiaro, dark grey and white, the only notable exceptions being
Niccolò Zeno which got a Claudus scheme with ochre and black and
Legionario which had green added to the standard greys. White spots were deleted in late 1942 as they provided aiming spots for British submarines at night. ID letters were sometimes painted over; if mantained, they were still brick red.
All surviving destroyers serving with the allied RM after the armistice had the hull painted in dark grey and the superstructures in light grey.
- Post WWII: the prewar measure was restored, but the NATO ID numbers substituted the ID letters.
About the decks: until the end of WWII the steel decks of RM ships were left unpainted: the crew holystoned them with lead sheets, which protected them from corrosion. So there's no true "deck grey" for RM ships, altough it seems logical that hard-pressed crews painted their decks with the standard issue dark grey instead of empoisoning themselves with the lead sheets. One thing is sure, there was no dedicated deck paint for RM ships.