From the IMDb:

This serial was reissued under the title "An Evening With Batman and Robin" in late 1965. There was no added footage. The program simply consisted of all of the episodes (complete with titles, credits and cliffhangers - exactly as they were shown in theaters in 1943) presented one after the other in one sitting. Contrary to popular belief, this was not done in response to the success of the 1966 Batman TV show. The TV show began on January 12, 1966 and "An Evening With Batman and Robin" was playing in theaters as early as December 10, 1965.