Here's a brief overview:
The USN's prewar gray was actually a very pale blue, while its deck gray was a neutral gray.
The colors worn by USN ships through most of the war were purple-blues, ranging from very dark and very gray to very pale.
In lat 1944, due in part to a shortage of blue pigments and in part to studies by the USN camouflage unit that concluded that tone was more important than color, the Navy introduced a series of neutral grays. Some, but not all, ships repainted in these during 1945. These neutral grays continued in use through about 1950.
So, in 1947 the PERRY would have worn neutral #27 Haze Gray on all vertical surfaces, with decks in neutral #4 Deck Gray.
We've got the #27 Haze Gray available in our Colourcoats enamels, and I'm sure we've got something close to #4 Deck Gray.
Cheers,
John Snyder
White Ensign Models
http://WhiteEnsignModels.com