Yes , I believe it is
According to Horace Kallen , Cultural pluralism refers to a society that contains a lot of different ethnics, but each ethnics still try to maintain their identity.
The U.S society in 1920s indeed consist of several group with different ethnicity due to the large number of immigrants that came in. But each groups tend to form their own communities in separate area rather than assimilate. This maintain the difference in their ethnic diversity.