According to Edith Reiter's 2014 book this instrument was completed on 25 May 1987 and originally sold to a buyer in Switzerland.
Howe & Hurd (2004) describe heckelphone #4988 as a model 36 voll cons.
As of 2017, heckelphone #4988 was located in Zurich, Switzerland, owned by and used in the Zurich Opera (Opernhaus Zürich), who is likely to have acquired the instrument directly from Heckel. It was played prominently by Portuguese-born oboist Samuel Castro Bastos in 2017 at the premiere of Manfred Trojahn's opera "Orest"