The model depicts NASA 905 (SCA) and Orbiter Enterprise, as they appeared after the Approach & Landing Tests at Edwards Air Force Base in 1977.
After completion of the ALT flights at Edwards, Enterprise went to Marshall Space Center in Alabama for mated vibration testing, and then to the Kennedy Space Center in Florida to conduct Ground Support systems tests.
In 1978, NASA sent the pair on a global "goodwill" tour, which included all major NASA center locations and well as the Paris Air Show in France.
The NASA 905 paint scheme is from this period.