This Estes version is based on the old Centuri Scram Jet kit #KF-4.
The Centuri kit didn't have the long continuous stabilizer. Centuri had two long separate horizontal pieces. The sub fins were missing on the Scram jet.
Pieces of Interest:
The long launch lug, 1/16" thick laser cut fins, the decal sheet features the kit name not the stenciled U.S. NAVY, a thick yellow coupler/engine block, two card stock alignment templates.