From reading more posts in this thread it seems like it doesn't matter what year the car is the floors all have a slope starting from the transmission tunnel going down to the door side.
This means you'll need custom made brackets, the original bucket seat tracks, or find seats with brackets meant for a sloped floor. There is a guy on this forum that has made solid aluminum seat brackets (no sliders) with speed holes (cause those are just awesome.)
I love them but machined aluminum is pricey but if I didn't have my old bucket seat brackets... I think I'd have done it.