All bonds or notes purporting to be issued under authority of this chapter, and executed as hereinbefore provided, shall, in favor of bona fide holders, be conclusively presumed to have been duly and regularly authorized and issued in accordance with the provisions herein contained, and no such holder thereof shall be obliged to see the propriety of the purpose of the issue, to the regularity of any of the proceedings relating thereto, or to the application of the proceeds thereof. Said bonds or notes shall be negotiable in all respects and to the same extent as other securities negotiable by the law merchant except as herein otherwise provided. Any of such bonds or notes, if properly executed by officers of the municipality in office on the date of execution, shall be valid and binding according to their terms notwithstanding that before the delivery thereof and payment therefor such officers shall have ceased to be officers of the municipality.