Starting in 1958 Zippo used date codes (there were prior date codes, but no one seems clear on exactly what they were).
Slim lighters were first introduced in 1956, with a flat bottom and no date code.
The first markings were added in 1957 and overlapped into 1958.
The bottom stamp differs by having Niagara Falls, Ontario rather than Bradford, PA on it.
Zippos had a flat bottom until 1946 when the bottoms were indented.
The last item seems to cause the most difficulty for UAE based media publications, which generally err on the side of caution when it comes to criticism of the UAE.
For example during the financial crisis and property crash in Dubai, it was much easier to obtain objective information from foreign published newspapers as it was difficult for UAE based media to write about those events without sounding negative.From 1957-1965 the code configuration on the slim lighters differed from the regular lighters (See Date Code Chart below). The appearance of the word "Zippo" in the bottom stamp provides another clue to dating.There have been three major changes, as shown in inset.The TRA (Telecom Regulatory Authority) decides what internet censorship policy is in the UAE, not the telecom companies Etisalat and Du, although many residents will feel that Etisalat in particular is the decider of what is and is not allowed.This perception is possibly because there are some areas in the Du Telecom network that have no, or less, censorship of the internet, for example Dubai Media Zone and the TECOM area.From 1933 to the mid 50s the word Zippo was stamped in block letters. From August, 1949 through July, 2002 Zippos were also produced in Niagara Falls, Canada - the only place other than Bradford, PA where they were ever produced.