More info...The fuel tank and strap changed with the introduction of the '74 1/2 model. This is when the fuel tank capacity increased to 17.2 US gals from 15.8 US gals. So with what Nigel has said, that makes 3 different sets of straps for the S30. Just trying to help you draw a line for the different usage. I can look it up in the microfiche for you if it will help others when ordering.
Edit: The Gas Tank Strap part numbers 17410-N4500 (RS) & 17405-N3400 (LS) are shown as being used from 09/74 - 07/76. That pinpoints the use of all 3 different sets. Hope that helps.