The Menorah had forty two decorations which were all an essential part of its body. When the Menorah is made of gold, it must feature these decorations. Even if even only one of the decorations is missing, the Menorah would be deemed unfit for use. However if gold were not available and the Menorah was made of a different metal, the decorations would not be required. 
Design
Contents:   Part I,    Part II,    Part III,    Part IV,    Part V,    Part VI,    Part VII