It looks like this bottle has a screw cap - and in that case, Dewar's spring caps were replaced by modern screw caps during the late 1950s and early 1960s. I can try to get a more specific date for you. In the meantime, leave your contact info here on the forum so if someone comes across your request and has what you are seeking, they can contact you directly. Ebay no longer allows these types of ****s.
Last edited by Jojo; 01-10-2013 at 02:11 PM.