According to Edith Reiter's 2014 book this instrument was completed on 1 July 1972 and originally sold to a buyer in the USA. It was the first heckelphone to be completed after a hiatus of almost 15 years in production.
Howe & Hurd (2004) describe heckelphone #4971 as a model 36 voll cons.
As of 2004, heckelphone #4971 was reported to be located in Pittsburgh (PA), USA, owned by the American Wind Symphony Orchestra.
The history of heckelphone #4971 remains largely unclear, but it is conceivable that the American Wind Symphony Orchestra purchased the instrument directly from Heckel.