you are correct, here's a picture of mine when I finished sheeting it. I was worried I screwed something up, but it's exactly right & both sides were identical.

When I finished sheeting the top of my first wing & flipped it over on the straight edge it had a slight twist & didn't lay perfect. I just put some weights on it while I sheeted the bottom & it firmed right up & stayed straight. I recall the manual stating that when you finish this step it will lock the wing into shape.

If you dig through some of the old build threads there are some who see this as a flaw in the kit because a symetrical wing should be perfectly symetrical, but I think the odds of you or I trying to modify the wing to make it perfectly symetrical are probably not too good.

btw, your wing is looking good!