IIRC, the cold start injector looks very similar to a regular injector. Rectangular plug with two contacts.
I don't believe they are interchangeable, however.
And yeah... they never came as just a pigtail. They are made into the injector harness.
There were only two injector harnesses ever installed in a V6 Fiero. One (the most common) has a flat connector, where it snaps into the main harness. The other (only used for some 88s) used a more square connector.
Aside from that... If you're running a 7730, you shouldn't need a cold start injector. Unless this is for a different car, of course.