The yellow diamond for the chain packaging shows up with different markings. Later ones have: 57704/1 printed under "Made in England". This is a odd numbering system used for a time for only a few parts. This is a whole other story and can be found in the spare parts packing tales elsewhere. Suffice to say, the 57704 marked ones seem to appear in later sets( post 1958?). Will have to see a number of mint sets to determine....