The NGA antiquities, an 1,800-year-old limestone carving depicting a scene from the Buddha's life and a 1,000-year-old stone likeness of the Hindu tantric goddess Pratyangira, were bought by the gallery in 2005 for US $1.5 million from Subhash Kapoor, the owner of the infamous gallery Art of the Past, based in New York.
An NGA statement released on Monday said the gallery would cooperate fully with investigations and would happily hand over the artifacts if they were indeed stolen.
"The NGA has conducted thorough provenance research into these two sculptures and is working closely with Indian authorities on the next steps," the statement read. "It is certainly possible they will be returned."
In 2014, one of the NGA's showcase pieces, the US $5 million Dancing Shiva, was returned to India by then-Prime Minister Tony Abbott after it was revealed that the piece had been purchased from Kapoor's collection.