What determines the stripe choice?

the over the top stripe was an optional stipe. it was "new" for 1973. it lasted through model year 76. the side stripe was also avabile but was another option. your car seems to have the body side mouldings running down the sides. the side stripe would not have worked for your car with this moulding. the over the top stripe was usally ordered with a vinyl top as well but not always. look for code v9w on the fender tag.