I don't know. The story has been published both ways.
http://www.freerepublic.com/focus/f-news/1132586/posts <-- Two versions here
http://www.boston.com/globe/nation/packages/kerry/061603.shtml <-- Boston Globe online (no registration required, long read, worth the time)
"A couple of weeks later, on March 13, 1969, a mine detonated near Kerry's boat, wounding Kerry in the right arm, according to the citation written by Zumwalt. Guerrillas started firing on the boats from the shoreline. Kerry then realized that he had lost overboard a Green Beret who is identified only as 'Rassman.'"
Here's an interesting tidbit from the Globe article ...
" Kerry's early departure meant that he was leaving behind a crew that had suffered through many bloody battles with him. Worried that crew members would be killed, he arranged for them to receive a safer assignment. When one crew member, Medeiros, tried to stay, Kerry "came and talked to me and said, `I really would like you to go. ... I'd like to know you are safe, or safer."'"
That's odd too...