The naming rights for the GM Building, one of the rarest opportunities in New York real estate, are officially in play.

During last week’s third-quarter investors call, Boston Properties president Douglas Linde included in his prepared remarks the following: ”We can report that we were able to retain General Motors in 114,000 square feet for 10 years at 767 Fifth Avenue, the GM Building. As part of the lease, we recaptured the right to name the building in…