I don't know, but consider contacting the Patriot's Point Naval and Maritime Museum in Charleston SC. The have the USS Laffey, of the same class, preserved as a museum ship. Pictures from the 2007 restoration effort show a deck of grey-painted material, although obviously I have no idea if that is original.

Consider emailing the museum and asking?

Also, I found a close-up photograph taken in 2007 that shows a piece of the "upper deck" (don't know the proper name, sorry) as grey: http://www.patriotspoint.org/news-and-events/wp-content/uploads/2012/04/120415_LaffeyHomecoming_009.jpg

edit: here's another photograph that definitely shows the deck as grey in color: http://www.patriotspoint.org/news-and-events/wp-content/uploads/2012/04/120415_LaffeyHomecoming_045.jpg