The 3 Carriers in shot when Gibbs heads to the navy yard are the CVN 65 Enterprise, CV 67 John F Kennedy and the CVN 75 Harry S Truman.
The "grenade" fragment that Gibbs shows to Vance actually only has the Russian word for "training" written on it, as in "training grenade" - a dummy used for military training and therefore it couldn't have detonated.