After installing AC or BX Is a Bonding Jumper Required when joining a Receptacle to a metal box?

BX is Trade slang for AC or Armored Cable.  The Internal Bonding strip made of cu (copper) or al (aluminum) should remain in contact with its flexible metal armor along its entire length.  This Bonding strip is used to hold the anti-short bushing or redhead (trade slang) from falling off and is used to protect any size wires from abrasion and Not just #4 awg and larger.  The armor of AC itself is suitable as an equipment grounding conductor as per 250.118 or 320.108.  However when entering boxes where a change is made in order to supply a receptacle, the receptacle must