Are there two versions of the set 6205? I own the LEGO set 6205 and I noticed from another picture on Brickowl and Bricklink the wing design is different. Is there an alternate version or did someone who had the set mix up the pieces and build it the wrong way?
To figure out which party made a mistake, compare everyone's work with the official art displayed on the box.

Short answer: Go compare images against the box art.



Detailed answer:

First, let's investigate and try to understand what the OP is talking about with some build dependency in the wing area of Set #6205.

So, upon going to both Bricklink and Brick Owl, we see the same curious image both sites are using, that seems to conflict with the original box art.

Hey, look, the fabled alternate build!



So, let's compare:  

LEGO alternate builds tend to add something of value that is visually or functionally appealing. 


Focusing our attention at the original's wing design, notice how the
tapered flow traverses smooothly back to the stern of the ship, versus
the squared off-bluntness of the alternate.

So... where's the further-appeal rational for the alternate here? 
is LEGO offering us a battle damaged version?


Let's nitpick this image's authenticity further.


A) The reflective glare obstructs the minifig, giving us that shine-on-you-crazy-diamond effect only the Pink Floyd fan would appreciate.  
B) The shot of the canon weapon is skewed here, but if official, would be aesthetically squared, and oh so perfect.




Furthermore, there is no proof of the existence of "Dash-Two" instructions.


When LEGO offers multiple builds of a set, they tend to add a dash
"-" and a sequential build number at the end of the set's name. 
So, if one existed, it would read "6205-2".

Dashy-Two, Dashy-Two! Where are you?




Finally, just Look at it.  On the surface it looks like a build mistake that anyone of us could make, but seriously, after looking deeper, does anyone really think LEGO would approve this?  

So, taken it in all together, these detail errors just wouldn't fly at LEGO.

Conclusion: The 6205 alternate build image is simply bogus, and should be ignored as an innocent mistake at Bricklink and Brick Owl.

But... That was some very impressive attention to detail, young Justan Ryan.