Estes Tech Pak Build Finished

The fins were glued on and the launch lug placed on the same side as the engine hook.

The model is "Designed for Technology Classes".
The only difference is rolling your own body tube. That, and you cut your fins out of heavy card stock.
Most all is standard rocket construction.
After all is dry, the tube has some slight wrinkles.
The tube is not as thick or as strong as a regular BT-50.

The only place I've seen these for sale is on the AC Supply website.
From their website:
"Scratch build your own rocket using authentic Estes components. Requires that the student manufactures his own body tube using materials provided. (IDEA: Order ACBT50 body tubes from below for a quick economical parachute recovery rocket) This rocket can withstand engines up to C6-7 without losing fins or other light duty parts. Lowest cost parachute recovery rocket available. Comes with or without engines."

Specifications
Length: 38.4 cm (15.1in)
Diameter: 24.8 mm (.976in)
Weight: 28.1 gm (1.0 oz.)
Can fly to over 1000 ft

They may have been produced to compete with the Pitsco "Roll Your Own" tube models made for schools.
Personally, I wouldn't hand these out to younger students. They wouldn't be able to roll the tubes successfully. It's not easy to do!