Did the Douglas SBD Dauntless have a second set of controls?
The Dauntless did have controls for the rear gunner- a pair of permanently attached rudder pedals and a control stick that was stowed away on the port side until needed. See:

https://www.tapatalk.com/groups/warships1discussionboards/sbd-dauntless-flyable-from-rear-cockpit-t2435.html

Juan Jimenez is correct that it would be very difficult to operate, what with the armour plate for the pilot and the radios right in front of the gunner. See here for a story of flying a veteran Dauntless where the pilot gets a brief familiarisation flight from the gunner's seat (it's mentioned in the fourth paragraph after "SBD Glider: Engine Out"):

https://www.aopa.org/news-and-media/all-news/2011/january/pilot/flying-a-national-treasure-the-sbd-dauntless

You can see the gunner's control view at the Smithsonian's walk-around view of the Dauntless, it's images four and seven in the collection (six shows the pilot's view and eight the gunner's real place of business):

https://airandspace.si.edu/collection-objects/douglas-sbd-6-dauntless

Photo seven