This is what I was able to dig up.
“It is unfortunate how misunderstood Colt’s Blackpowder Series is. Colt was finally convinced by Val Forgett of Navy Arms to reintroduce Colt Blackpowders in 1970. Obviously since Colt had no machinery or tooling to produce black powder revolvers, but Uberti was in current production of Colt Blackpowder Replicas for Navy Arms, the relationship was established. The difference though is that Uberti made rough castings according to Colt’s specs and sent them as parts sets. Colt received the parts sets, inspected them for correct specs, then hand fitted, filed, polished, case color hardened & finished all “C” Series revolvers.
In late 1973, Colt made arrangements to use a new supplier of these parts sets, Lou Imperato, who was Colts largest American distributor. Imperato supplied parts for the 3rd Model Dragoon in 1974, but due to Colt’s labor disputes was not able to produce Dragoons until 1975. The “C” Series came to an end in 1976.”
I had a “C” series Colt (a 51' Navy) but, if I remember, it came in a tan like box, not a black box that I purchased in 1977.
Does Alder address this in his book?