I won't call myself an expert on Color Flows. I own one, and have done extensive research on the model. In real life, any owner back in the day could have added the red jewels to any early model, as I'm sure that was a popular thing to do. I don't think they were an "option" to speak of in 50 or 51, because they weren't introduced until 52. If you look at original Sears catalogs or advertisements, you will never see a Color Flow with BOTH the rear carrier JC Higgins chrome emblem AND the red tank jewels. This applies to both boys and girls models. The emblem is only 50-51 and the red tank jewels are only 52-53. On a different note, Sears never called these Color Flows, the name is something us collectors have adopted since Sears, for unknown reasons, never had a model "name" for this bike, only referring to them as the "Finest" model available. The term Color Flow was used to describe the band of color that "flowed" from the chain guard into the rear fender brace.