ORIGINAL: Tarasdad

Swapping them end-for-end isn't going to change the spacing. Also, both wing panels are identical in spacing, just mirrored.

<span style="color: #ff0000">Yes both wing panels right and left are symmetrically identical.
We cannot tell by the pictures if the spacing in one wing side is equally spaced.
We often see the ribs near the root being closer than the ribs further away.
That is why I suggested to check that. </span>

Compare both LE and TE pieces with one another and confirm that the spacing is equal.

<span style="color: #ff0000">The LE spacing would be the same as the TE spacing and it is if all the ribs are parallel which is what we expect. However if the spacing is not the same and each wing has closer spacing near the wing root then using the right wind piece on the left side might still match the spacing but would put the piece upside down. This may affect the contour. Like the LE may have a preshape that has to be correct. </span>

Check that the provided sheeting and ailerons will extend far enough to fit if you build the wings as-is. If both are true and the spars are long enough I wouldn't worry too much, just build them as they fit. One of the many things that can happen to paper plans is shrinking or expanding due to temperature and humidity. I admit that 1/2" in the space of one wing panel is more than you would normally expect, but still within the realm of possibility.

<span style="color: #ff0000">I just cannot see the paper drawing having changed by 1/2 inch.
Perhaps the wrong LE and TE have been put in this kit ? That kind of thing has been seen before. </span>