If you built the leading and trailing edges on and to the plans it won't make a gnat's ***** of a difference. If, however, the chord of that wing (total width) is compressed because the ribs were angled it will make a tiny difference (less lift vs. the opposite side). Once trimmed in flight you'll never detect it because of the dihedral built in . . . unless it was a major difference.

The LT-40 is a very forgiving and self-correcting design. I helped an Explorer post build four of them and you never saw four differently constructed versions of the same kit with no intentional bashing. There must have weighed a full pound different between the four (one group used two bottles of Titebond and another only half of one bottle!). But they all flew very well and it was really hard to pick the heavy one unless you flew it immediately after the lightest. Great choice for a trainer and first build.