I have a feeling that the storage area had fertilizer or something like that in proximity to the kit parts. The corrosion under the rivet heads and on the spar is concerning. That would be near impossible to correctly address. I would look for a kit in better condition, and add this example to the "primer wars" conversation as an example of "why I prime".
RV-6A. Mattituck TMX O-360, FP, GRT Sport EFIS, L3 Lynx NGT-9000
N184WM reserved (RV-8)....finishing kit in progress. Titan IOX-370