If you look at the print shown by TCM, it clearly shows 1928. Whether this film needed to premiere on both East and West coasts, a la the Oscars, is immaterial. The print says 1928. Would someone please change the date?
This film was originally released in 1928 as a silent film and it did not do well. DeMille re-released it again in 1929 as a talkie and it did slightly better. The copyright date of 1928, to which you refer, is correct. The film, in the version seen, is a 1929 release. Your assertion that the date used by TCM and IMDB is "wrong" is incorrect.
Remember When Movies Didn't Have To Be Politically Correct?