I just found this on the Smith & Wesson Forum. I guess that makes mine October of 1942 or early November 1942.

"I just received my factory letter and it confirms that Victory revolver number V158896 was shipped on November 20, 1942 to the US Navy, Oakland, CA. This is a standard 4 inch barrel Victory revolver in 38 Special with "U.S. Navy" marked on the top strap. This is the only military marking (no flaming bomb mark or a "P" on the frame, etc). The revolver has all matching numbers with the exception of the grips. "