(1) For the purpose of determining the statutory basis of existing units of local government after May 2, 1977, each unit of local government organized under the general statutes authorizing the county manager form of government shall be governed by the following sections:
(a) 7-3-301;
(b) 7-3-303;
(c) 7-3-304;
(d) 7-3-305;
(e) 7-3-312 (2);
(f) 7-3-313 (1) or (2);
(g) 7-3-314 (2);
(h) 7-3-315 (1);
(i) 7-3-316 (2);
(j) 7-3-317 (2);
(k) 7-3-318.
(2) Commissioners are elected to 6-year terms. The size of the commission shall be established by ordinance, but it may not exceed five members.