just my 2 looneys worth..thats 2 bucks to yee usa folks...
the picture of the black simple interior with guages and 4 speed and button horn wheel would be the basic, including a boss351..reason i say is they wanted the boss faster then any of them, doh, so less weight and more power equals a lotta horse dropings, and posi rubber left on pavement..the next "basic plus?" would be the plain all black with no woodgrain or chrome..the shrome and woodgrain is grande and mach1 with pretty chrome and wood grain all over....if yours came with no chrome on tach/guages, and no woodgrain and no plastic over metal on passangers side..then id bet it is the ALL black one not the button one not the wood grained one..did i repeat myself enough times..doh, sorry..just wanted to make it as best as i could....
hope that helps...
so take a pic of your interior..put it up here..and that will help sherlock better to answer ?