I only have two original Enerjet engines, both are E24-7s meant for my Enerjet Nike Smoke.
This one has a hand written number on it, "477". You'd think that might mean April of 1977, but the Enerjet product line only lasted a few years.
To see the 1972 Enerjet catalog: CLICK HERE
The casing looks to be fiberglass, the nozzle is graphite.
There is a bead of epoxy around the nozzle.
The upper end has an old style paper cap over the ejection charge.
One thing that hurt Enerjet sales was the price. Each E24 engine was $4.00 in 1972. That was way out of line for most hobbyists.
Let's hope that isn't a factor for the new Quest 18mm composite engines.