The S-Foils are way different, turns out. After you wrote this, I went and took a gander, this is the comparison I get:

[hider=Profile]
T-65 X-Wing, Original Star Wars
[img=http://photos.imageevent.com/afap/wallpapers/movies/starwarsanewhope/X-Wing%20Fighters.jpg]

The XJ, for lack of better designation
[img=https://lh3.googleusercontent.com/-l1wG7JFR0G0/VHjlA3L3H9I/AAAAAAAAEmE/bEr_U0b6qe8/w1920-h816/o7XbctM.jpg][/hider]

[hider=From head on]
T-65 X-wing, Original Star Wars
[img=http://media.liveauctiongroup.net/i/5736/8632912_2.jpg?v=8CE70FDFAF1B540]
XJ
[img=https://lh6.googleusercontent.com/-om9PFVaK-Rw/U808Pd-3LDI/AAAAAAABjWk/syn22ejUKVA/w1907-h750/RalphMcQuarrie%2BXwing-4.JPG][/hider]

Different S-Foils, the top offset from the bottom so that they fit flush, and no visible R2 unit in tandem with the pilot.