Not a big deal at this point
If they ever had chems (which we know they did) the existence of a few odd shells would be a certainty. That would be true even if Saddam had been fully cooperating.
They will need to find a stockpile to give any credibility to the WMD issue.
Still, hyperventilation and heartburn will be rampant in certain liberal quarters for a few days as they wait for a possible other shoe to fall.