Nice lamp, and it deserves to be electrically refurbished, for peace of mind safety reasons if nothing else.
The ‘E1260’ isn’t any kind of patent reference and it’s not an electrical safety standard either. I saw another in a more distinctive art deco style that was said to be from the 1920s-1930s marked ‘PAT APPLD FOR’ with an ‘E712’ mark, so I suspect these are manufacturer style numbers, but I don’t know who from.
Note that these ‘jaedite’ lamps were often made with synthetic ‘jadeite glass’, which was very popular in the US in the 1930s and 1940s.