The default phone set for CMU Sphinx2 is a DARPA-bet derivative, with noise-phones and without lexical stress. This is similar to, but not precisely the same as, the CMU Pronouncing Dictionary, CMUDICT.
In 2000, the Sphinx 2 default phone set was modified to remove "deletable" stops, and to split the TS "phone" into T and S. The phone set that is used for the dictionary must match the set of phones in the acoustic models.