Unique Hot Wheels Part Number by model/color starts in 2011

Before 2011, Hot Wheels Mattel used a numbering system where the part number corresponded to the casting or model, not the color variations. For example, in the 2010 mainline series, the Hot Wheels part number R0971 ('67 Pontiac Firebird 400) was available in three colors (green, red, or blue) and shared the same part number across all three colors.

However, starting in 2011, a unique number was assigned to each model/color combination. For instance, the 2011 mainline '10 Ford Shelby GT-500 Super Snake was offered in three colors (blue, maroon, and yellow), each with its unique Mattel number. The blue variant had the Mattel number T9673, the maroon variant had T9932, and the yellow variant had T9994. This change allowed for better organization and identification of variations within the same model.