That's an interesting question, particularly as you raise it in connection with Jubilee!, which long had an official real-only policy. Evidently, this is no longer the case (it's been awhile since we last saw the show, and we weren't convinced back then).
There is, however, one remaining topless revue in Las Vegas that is adamant about all its performers being entirely natural, and that's the catchily titled MGM Grand's Crazy Horse Paris. The show recently hired its first American dancer, but until that point all the performers in the cast had formerly appeared in the original Parisian Crazy Horse Paris. The dancers, who appear virtually nude, are all classically trained in ballet and are chosen to be indistinguishable on stage in terms of height and breast size and shape. The "magic" of the performance is in the choreography and lighting effects.
The Las Vegas production has also featured celebrity guests including burlesque queen Dita Von Teese and actress Carmen Electra (the latter has now appeared three times), while Pamela Anderson guested in the Parisian original.
On a final note, while the author of our Topless Vegas guide was reviewing all the erotic revues in town, he noted how the cast of Sin City Bad Girls, performing at the Las Vegas Hilton, looked remarkably "real." A word with the producer revealed that only one member of the cast was augmented. Whether that still holds true, we're not sure, but we do know that Arnold Snyder gave the show a rave review all-round (not least for its star Lorena Peril, who does not appear topless, but still commands the stage with her vocal excellence.)
