In relevance to a recent post, this is how a 1969 bottom stamp should look. : r/Zippo
Zippo - We've heard some wild rumors about the meaning of the bottom stamps on Zippo lighters. Some say it's the quality rating of the lighter, others say it's the inmate number
Zippo - Lighter - Zippo 1993 Chevrolet Corvette 1969 of 1 - Catawiki