>>33237718I think it's extremely plausible.
People have noted time and time again how similar the designs are to each other. This is unlike the Dragonite/Gyarados theory where its solely based on color and likely false. Theyre TOO similar, to the point where Butterfree doesnt match Caterpie whatsoever, but looks almost identical to Venonat. People also make qualms about the difference between moths and butterflies, but they would've only been named that way after it got to the US, hell potentially midway through japanese development. So that point is irrelevant.
More importantly, though, we know for a fact that RG's development was extremely messy. The Pokemon designs weren't designed like they are nowadays, where they have a dedicated team, they were just kinda made as they were going. Even the final product is riddled with glitches, small and big, so the idea that the sprites may have been unintentionally swapped at some point in development. It's not like it's the only thing that people are suspicious of getting swapped in the confusion.
