I found 2 of these today, one in yellow straw and one clear. I have closely looked at at it and it's a 1 but with the seriff at the base as well as top. Both pieces are from the same mould and it is dated 8-50::: for 1956 for the first one and the second is 8-50:::.. for 1957 .These are mould mates as both have 3 underpoured drips in the exact same spot and exactly alike and matching mould numbers. Could it be mould wear that caused the 1's to have the extra reversed seriff at the base? I don't think so because wouldn't the mould embossing at that wear point wear even more over the next year the mould was used? Both 1's are exactly the same. Any thoughts and please do post to ICON.