probably correct, only two kids in one local family had Fastbacks, one with the "rams horn" handlebars. They were sidelined to sidewalks.
the mag sprocket which I think was part of the Krate models, did show and set the styling standard for a short while. Then...

the krates and fastbacks both fell out of favor fast as it was "proto-bmx" that took hold.
Slick Chicks with welded in reinforcement tubes, tractor tread tires, ( the advantage of the 1 3/4" rims - lighter than the smaller, wider 2.125" rear version ) other mods - ditch the kickstand, chain guard, cut off the rear strut bar hoop, struts to the inside and fender washers on both sides. The local Schwinn shop took a picture to send to Chicago, they knew something was up but did not know how to comprehend it.
"rat trap" pedals and absolutely no reflectors.