Could absolutely prevent firing. The air travel pulling fuel up the pilot jet is very low. You need far more air to move fuel out of the main jet. Sounds like taking the carbs out was a smart move, nicely done!
So actually they were backwards on #3 also, but that one had at least a little fire based on the plugs. Also the gasket between the vacuum bowl and carb was upside down on two of these. Will put them back on the bike to try instead of eBay haha. We'll see : )