Village districts and precincts established under the laws heretofore in force may adopt the provisions of this chapter, and thereupon shall have the rights conferred thereby and be governed by the same except as hereinafter provided. Unless they do so, the laws under which they were organized shall continue in force as to them, notwithstanding their repeal in general terms. In any case where a village district or precinct heretofore established by special act is authorized to hold its annual meeting any designated time, the time for such annual meeting so designated in such special act shall govern the holding of such annual meeting unless said village district or precinct shall otherwise vote in adopting the provisions of this chapter.