According to Cpt Robert Rodenhouse (A/C):

While on Johnson Island, the B-29 plane was named. Rodenhouse and his crew had all been smoking cigarettes at the time, some of which were: Chester Fields, Old Gold, Camel’s, and Lucky Strikes. After pondering for a moment, Rodenhouse replied, “Lucky Strikes … Hey, every time you fly and drop a bomb, that’s a strike mission, a lucky strike means you get back home. Let’s name it the Lucky Strike.” So, with that, the B-29 airplane was named. Since they were still on Johnson Island, the Navy painted the name, Lucky Strike, in big letters on the side of the plane.
[“Oral History – Mr. Robert Rodenhouse”, Veteran’s History Project, p. 7]

The Lucky Strike was assigned to Crew #3903.  Other crews that flew the airplane included #3918.