The majority of exterior night sequences of "Rocky" were shot in
Philadelphia by a non-IATSE crew that had worked on earlier New York
films by John Avildsen. Some of this crew are listed as "second unit".
But this was not second unit in the usual use of the description. We
shot scenes involving dialog that were part of the finished movie and
several of these crew members were thanked by Avildsen when he accepted
his Oscar for Best Director.
(Explains what is behind "second unit" other-crew credits.)