I found this book that said they were not the same woman, but the author didn't give any evidence: Squires, S. (Ed.). (1990). Asconius Commentaries on Five Speeches of Cicero. Bolchazy-Carducci Publishers. Page 148.
First of all, at the time Sallust had written his book, Fulvia Bambula was a quite famous person. I believe, it would be strange if he would have said "Fulvia" yet had omitted "Bambula".
Moreover, his words give the impression that she had no personal political value (cf. his passage about Sempronia Tuditania), and yet had much financial difficulties:
He had long had a criminal intercourse with Fulvia, a woman of high birth, but growing less acceptable to her, because in his reduced circumstances he had less means of being liberal
But Fulvia Bambula was both young, ambitious, and one of the richest women in Rome (after inheriting her mother's property). That makes hard to believe she looked for a rich yet boring lover.
After all, the name "Fulvia" was not so uncommon. Sallust mentioned two persons named Fulvius who supported Catiline, so that woman could be the relative of one of them.
The two identities are listed separately in biographical encyclopedias of Rome because there is no concrete statement by ancient authorities one way or the other that Sallust's Fulvia is the same as that who came later.
Nevertheless, it is highly likely that they were the same person because the later Fulvia was a highly active political meddler and notorious tramp, so it would have been entirely consistent with her later behavior for her to have been the young mistress of Quintus Curius, especially if we consider that this association would have consistent with the political factions involved. At the time of the Catiline conspiracy she would have been about 20 years old. She married Clodius the next year, at the age of 21.