Yea, Reed is right. It uses Episodes 1, 3, and Italian 23 (OVA 2). It uses almost all of the footage from each of the episodes. Episode 1 is cuts out the part where Fujiko explains who Rebecca is because they have that part shown on a TV screen news program. Episode 3 they cut out the part where Nix says to Lupin that they met for a second time, it doesn't count them as meeting in episode 2 in this I guess. And OVA 2 it cuts out roughly the first 2 minutes of the episode.
I've seen it with some rough subtitles and its not that bad of a special, just a little cliche the way it ends.