It's kind of implausible. A Soviet spy satellite would have found the sub hidden in Maine very soon after that. The Russians would have called that an act of war.
You'll like reading upon this:
GSF Explorer, formerly USNS Hughes Glomar Explorer (T-AG-193), was a deep-sea drillship platform built for Project Azorian, the secret 1974 effort by the United States Central Intelligence Agency's Special Activities Division to recover the Soviet submarine K-129.[3][4]
