Kerry was in the inactive reserves from 3 Jan 1970 to 1 July 1972. He was then transferred to the Standby Reserves (inactive) until 16 Feb 1978. A brief summary of his naval service appears in the 24 May 1986 letter from the Department of the Navy in response to a request from Kerry. See http://www.johnkerry.com/about/Request_For_History_of_Service.pdf
DD215
The source document for Kerry's release from active duty is included in his Release from Active Duty endorsement dated 2 Jan 1970. See http://www.johnkerry.com/about/Release_From_Active_Duty.pdf
His DD214, at least the one on his site, appears to be missing a cover page or letter. There are only pages 2 and 3. Those pages aren't dated. His separation date from active duty is given as Jan 3, 1970, which tracks with his release from Active Duty endorsement that gave him 1 day travel. The DD215 "correction" doesn't seem to contradict what was on the DD214 if you read the date day/month/year. In any event, he didn't receive his honorable discharge in 1970, only his release from active duty. He received his honorable discharge from the Reserves in 1978.
Lehman was not the SECNAV in 1968. See http://www.history.navy.mil/faqs/faq37-1.htm . I don't see any point in trying to track down the validity of an erroneous reference.
John F. Lehman, Jr. was born in Philadelphia, Pennsylvania on September 14, 1942. He received a Bachelor's Degree in international relations from St. Joseph's College in 1964, and spent three years in the Air Force Reserves while attending Cambridge University. In 1968 he left the Air Force Reserves and accepted a commission of Ensign in the Navy, where he advanced to the rank of Commander. After serving on the National Security Council and as Deputy Director of the U.S. Arms Control and Disarmament Agency, he was president of Abington Corporation. Lehman was selected to be Secretary of the Navy on January 23, 1981 and remained in that post until April 10, 1987
Good luck with the reporter.