Persons who succeeded to positions in the municipal court upon its establishment shall receive credit for continuous prior service in superseded courts and in the sheriff’s department or constabulary of the county, and, in addition to the minimum rate, such persons shall receive the annual increments commensurate with such years of prior service up to the maximum rate set. This section applies to municipal courts provided for in former Articles 3, 7, 12, 13, 15, 18, 22, 23, 29, 31, and 32 of this chapter.