The vent will be stamped with the WOOD DALE, ILL. city name. There MAY have been some early non-stamped vents for kettles made in Wood Dale after the move from Chicago, but it's hard to verify.
The vent-code cheat-sheet is a work in progress, but this version is close to final. Handy to have a copy in the glovebox for those sudden curb-alert finds.
For those wondering, the very first tabs were welded onto the vent as a separate piece. After that, the tab was stamped out with the vent itself. Note the shape of the vent tab also changes, and I need to update the chart to reflect the reality that WOOD DALE vents are square - at least some are.
@Craig would know for sure what years went with what tab style, but we keep learning new stuff as some of the old kettles resurface.
