68. Manner of affixing Central Excise Stamps.- Every Central Excise Stamp shall be so affixed that—
(a) the box or booklet on which the Central Excise Stamp is affixed cannot be opened without tearing the Central Excise Stamp;
(b) when it is affixed to a box, the Central Excise Stamp shall cover one side of the inner tray and a part of the rear or bottom or front or top of the outer box, and the Central Excise Stamp itself shall not be covered by either the factory's label or any advertisement label.