How can I determine the manufacturing date on a Peachtree product?

For units manufactured before 1991: A silver-grey identification label is applied to all products with glass to identify type of glass, date and locations of manufacture.

Units with aluminum spacer bar between glass surfaces: Glass identification label will be affixed to the spacer or identification information will be stamped on the spacer. The spacer is located around the windows perimeter, between double panes of glass.

For units manufactured in 1991 and after: Glass identification label will be affixed to unit under the glass stop, or on swiggle between the two panes of glass. Note: If stop is not accessible, check under liner of operating window.