sounds like 2383 all right. I sometimes get my 15mm movie film back where the lab has used waste 3383 16mm print stock as a leader. Semi translucent bluegreenish. Iridescent on the back side.

If developed as B&W the edge print would be black, and would for current stock just say Kodak and the year it was made, ie "Kodak 12" older stock would say Eastman Safety Film. The edge print may be Microscopic as the Sony SDDS sound system used the very edge of the film. they solved the conflict by eventually only putting the edge print in one layer.

If you were to run a sample though c-41 with some images with about the right exposure you should get some sort of colour.

BTW, the print stock has it's own process, ECP-2 (Eastman Colour Print two)