In the application of this Act to existing companies, It shall apply in the same manner in the case of a limited company, other than a company limited by guarantee, as if the company had been formed and registered under this Act as a company limited by shares; in the case of a company limited by guarantee, as if the company had been formed and registered under this Act as a company limited by guarantee; and in the case of a company other than a limited company, as if the company had been formed and registered under this Act as an unlimited company:
Provided that reference, express or implied, to the date of registration shall be construed as a reference to the date at which the company was registered under the Joint Stock Companies Acts, or under the Companies Act, 1862, as the case may be.