No provision of this act shall apply or be construed as having heretofore applied to any village incorporated or reincorporated under Act No. 278 of the Public Acts of 1909, as amended, being section 78.1 to 78.28 of the Compiled Laws of 1948, unless specifically adopted by the electors as a part of its village charter. The provisions of this act shall be deemed to be in the nature of charter provisions for any village incorporated thereunder or subject thereto and any such provision may be altered or removed by amendment adopted by the electors as provided in Act No. 278 of the Public Acts of 1909, as amended, provided that the effect of the amendment is such as might legally be accomplished by charter provision in the case of a village operating under Act No. 278. All such amendments heretofore so adopted by any village incorporated under or subject to this act, and all actions heretofore taken and all bonds heretofore issued under or in accordance with such amendments, are hereby validated to the same effect as if the foregoing provision had been in effect when such amendments were adopted.