It’s a real, not computer, model but was created to aid design and construction, not just as a promotional device, so I think it qualifies as a BIM.
The original Sydney Opera House on show at the University - News & Events - The University of Sydney
The perspex model, which took seven years to build, will be on display at the Faculty of Architecture, University of Sydney until December this year. The University is hosting the first public showing of a 1966 model of the Sydney Opera House in more than 30 years.”
Sydney Opera House model found after 30 years - www.nzherald.co.nz
“The model, which was based on 8,000 detailed drawings, is 4.5m long by 3m wide by 1.8m high. It was designed to help contractors solve the engineering challenges posed by the unusually shaped building, such as how to install ventilation and air conditioning systems.”