That is not really correct based on the available information. Look at the title of the article itself,

The Rock movie plot ‘may have inspired MI6 source’s Iraqi weapons claim’

The source of Mi6, claimed that Iraq had this. But Mi6 was clearly suspicious, because chemical ammunition are usually not stored in glass containers. This is given just below of the line you quoted,

MI6 accepted this possible flaw to the intelligence, the report adds: “The questions about the use of glass containers for chemical agents and the similarity of the description to those portrayed in The Rock had been recognised by SIS. There were some precedents for the use of glass containers but the points would be pursued when further material became available.”