The Colt / STAR manufacturing agreement to sell the STAR Model D in the USA as the Colt 'Pony' never really got off the ground.
A very few pistols, some say around 25, examples were made up and marked as 'Colt' . The project fell apart for some reason after that and no more were made or sold.
The idea was to sell the popular STAR Model DK 380 in the USA as it was no longer importable due to the GCA68 point system.
Colt & STAR decided that all the parts (forgetting the frame for a moment) would be made in Spain as they still continued to be mfg'd at the time.
Then those parts imported to Colt. The slides were unmarked and Colt would roll mark them with their markings, numbers ect.
Regarding the pistols Frame:
One story is that the frames were made in the US at Colt or a contractor for Colt.
Another is that the frames were also made in Spain by STAR and were of special dimension to add importation points.
The dimensional difference was the addition of a lanyard loop on the bottom of the grip to add to the height of the pistol,,one of the things that the ATF scored for points.
The other thing was the small adjustable rear sight on the slide.
...So the question..Why make the changes to make the gun importable if you are not 'importing the gun' and just the small parts instead.
This latter story/position makes sense. But the one about the frames being made by Colt in the USA is more often cited.
Take your pick...
The ser#'s were prefixed by the letters 'CPA' for Colt Pony Automatic.
The GCA68 demands a prefix to the guns ser# to denote a model separation. Colt chose that letter sequence.
After those few factory test & show guns were made, no more of the Colt/STAR partnership Ponys were made it seems.
Next Iver Johnson bought the rights to the particular gun in the USA. They went ahead and manufacture slides and it appears they bought up NOS Colt frames as some of the IJ products have those 'CPA' ser# prefix.
The small parts are STAR mfg and they sold the pistol as a 'Starfire' which was the US name of the pistol when imported and sold here by Garcia. They must have eventually mfg or had frames made to supply their production.
Either the IJ or the next maker changed the frame a bit by lengthening the grip tang.
Next Firearms International got into the ring. They started selling the same pistol as the 'Model D'. I believe they bought the rights from IJ,,but it's confusing at this point. Maybe they were just making the pistol as an outright copy.
I'm not sure if they were making the pistol themselves or still relying on STAR for small parts,,or what was going on.
These are steel frame pistols
The original STAR Model DK 380 pistols (and Model DKI 32acp) are great little alloy frame pistols w/ swing link locked breech actions. Very small and light weight. Pretty snappy in hand when fired though!
I've had two of them and both functioned perfectly with FMJ. Not so well with any HP type ammo I tried.
IIRC, a Model S magazine will fit and give you added capacity with the mag hanging down below the frame. Good for the spare mag I guess.