AAbsolutely not. "Dreamgirls" is a fictional work, adapted from a 1981 successful Broadway musical inspired by the real-life story and success of The Supremes. The film version references elements of Motown history to add backstory to the musical's plot, and there are many homages to a number of distinct 1960s/1970s R&B stars (besides The Supremes and Motown acts such as Marvin Gaye, the Jackson 5, and Tammi Terrell, non-Motown artists such as James Brown, Jackie Wilson, Aretha Franklin, and Sly & the Family Stone are also referenced). This is similar to "The Five Heartbeats", a film based upon the histories of The Dells, The Temptations, and other 1960s/1970s R&B groups.It's pretty clear that the Supremes provided the starting point for the story, but the plot takes many turns which differentiate it from their actual story. It's a lot like "ripped from the headlines" plots on Law & Order, which start with a real event but add and/or change elements to fill out the episode. Florence Ballard never had an affair (or a child) with Berry Gordy, and she died without making a comeback after being forced from the group. She was also not the permanent lead singer of the group before they became famous.. Diana Ross left the group in 1969. Some of the differences with reality were part of the story from its conception, but others happened because of things that came up during the show's development process.
A"Dreamgirls" was originally a Broadway musical, and the film retains about thirty songs or song snippets from the original stage musical, with four new songs ("Love You I Do", "Patience", "Perfect World", and "Listen"). Since the film is a musical based on a Broadway production, and, again, is not actually a Motown/Supremes biopic, there is no need to use Motown songs or imitations of such. The only song that could be labeled an imitation is "Perfect World"; however, that song is presented as a parody of the Jackson 5's hits more than anything else.However, a number of the songs do pay homage to the Supremes and the other R&B girl groups of the day (for example, the instrumentation for the song "Dreamgirls" is rearranged from its original Broadway orchestration to sound more similar to a Motown Funk Brothers band track, and the distinct influence of The Supremes' styles of singing and harmony can be distinctly heard on most of the Dreams' songs). The "Dreamgirls" film also takes inspiration from sources outside of Motown: strains of James Brown, Jackie Wilson, Little Richard, Etta James, Aretha Franklin, and Donny Hathaway can be distinctly heard throughout the film.Incidentally, if "Dreamgirls" were actually a Motown biopic, only a handful of its songs should actually have the Motown sound, in order to be historically accurate: "Love You I Do", "Dreamgirls", "Heavy", and the "I'm Somebody" medley. The other songs are either (a) performed before 1963, before the Motown Sound had fully developed and the company's releases were closer in style to the other R&B/soul releases of day, (b) performed in a venue for which Motown would have rearranged its songs to make them more palatable to a particular audience (i.e. Las Vegas), or (c) performed after 1973, by which time the Motown Sound was becoming less distinct again, due to the changes in the soul music industry at the time.
