Good info. Kerry arrived in-country on November 8, 1968 and left 26 March 1969. He was on combat ops 9 Feb-March 22 1968 WESTPAC and the Gulf of Tonkin on the Gridley 23-27 March 1968 and April 1 to May 5. He arrived on the Gridley 8 June 67.
Based on your info it appears that Kerry earned two stars on the Gridley --Tet Counteroffensive (Army, Navy, USCG): January 30 to April 1, 1968 and Vietnam Counteroffensive, Phase IV (Army, Navy, USCG): April 2 to June 30, 1968
Kerry earned only one star in Vietnam, according to your info. Some more questions for Kerry.
You just have to be in-country during the campaign. So it appears he is eligible for the 4 stars.
I'm starting to get dizzy with Kerry's dates.
Other resources (The book "Tour of Duty" for one)show Kerry on the Gridley 12/67-6/68. His Gridley orders are unclear when he was to report. And the History of The Gridley show Kerry on it from 6/67-6/68. John Kerry's web site says 6/67 report date.
And I'm sitting here wondering why I'm spending so much time on John F'n Kerry.