A ribbon is another means of displaying a medal. And the Vietnam Service Medal patch pictured in Gerhed's photo has each campaign year indicated. Please note that a campaign does not necessarily coincide with a calendar year, but a tactical change in military or political action/direction. So Gerhed's patch may not be a true reflection of how many campaigns he served during the Vietnam action. The ribbon with any additional star(s) is typically worn on the rack... And there are a total of 17 campaign stars authorized for the Vietnam Service Medal. Personnel are authorized one bronze campaign star for each qualifying campaign with a silver star worn in lieu of five bronze stars.
Long winded yes, but I hope that answers your question... And no, I did not serve myself. Wanted to but getting glasses prevented me becoming a Naval Aviator like I wanted to. My father served over 27 years and has 4 bronze stars on his Vietnam Service Medal. He was selected for Admiral (O7), but declined offer and got out.
Scott