The earliest #402 bowl was definitely more of an orange-red hue, described in advertising as "Chinese Red".The red #402 bowl supplied with the 1970s Friendship pattern collection differs from the red 402 included in the #400 multi-color mixing bowl set, although it is similar to the shade of the earliest red 402s of that set.├ A Glossary of Terms ├ Dating Pyrex Kitchenware ├ Pyrex Ware Patterns │├ Pyrex Pattern List │├ Pyrex Pattern Browser │└ Pyrex Pattern Timeline │ ├ Standard Patterns │ └ Non-Standard Patterns ├ Pyrex Opal Ware Shapes ├ Pyrex Model Numbers ├ About Pyrex Item Numbers ├ About Pyrex Colors ├ Pyrex Solid Colors ID Chart ├ Pyrex Promo Accessory ID ├ Vintage Pyrex Advertising ├ Pyrex Catalogs & Brochures ├ Patent Database ├ Videos & Links └ Accessories/Books/Apparel Estimating the age of Pyrex opal glass kitchenware can most often be done by observing a few basic characteristics. Production of opal ware commenced in 1936 after the merger with Mac Beth-Evans Glass Co. The plant there would be used to produce a more durable messware for the military. in a downward curve below forming a broken circle of sorts around the name. No model number or other information was included on the earliest pieces. 1950 or shortly thereafter, the registered trademark symbol "®" was added below the name, the encircling wording became TRADE MARK above the name, with MADE IN U. These appear to be related to either molds or production runs. Patterns The first pieces to have a decorative graphical pattern applied appear to have debuted in 1956.While colors and styles of decoration reflected consumer tastes at the time of production, the first thing to look at is the backstamp. But the product would not be branded Pyrex until the debut of kitchenware made from it nearly a decade later. New patterns were introduced in keeping with changing tastes, so they can also give clues as to time period.
#500 dishes sold in 1959 and after in any color or patterns, therefore, should have the later style lids.
In 2010, Rolex mostly abandoned their conventional numbering sequence in favor for a mixed (aka random aka scrambled) serial. Random examples of these indecipherable numbers are "OT23Q257", "12345J78", and "345X29VN".
* We have seen G serialed watches that were produced in 2012, so Rolex is using both the mixed and the G at the same time.
The serial number is traditionally located at 6 o'clock between the lugs and under the bracelet.
In 2005, Rolex began engraving the serial number on the rehaut (French for 'flange') between the dial and the crystal as well as the 6' o'clock location.