§ 4-a. Banks to display signs. Every banking organization having as its purpose or among its purposes the receipt of deposits, shall continuously display a sign, or signs, as prescribed by the superintendent of financial services, at each station or window within the state where deposits are usually and normally received in its principal place of business and in all its branches indicating whether deposits are insured, and if insured the name of the insurer and the extent to which each depositor is insured. Signs in non-insured banking organizations shall clearly and legibly state "DEPOSITS NOT INSURED", all in letters of the same size and character. No sign shall appear in any non-insured bank with regard to insurance or deposits except as herein prescribed.