Both early and late style upper and lower arms are the same for Amazon and 1800, although I don't know if the newer style were implemented simultaneously (1800s tended to get new stuff first). For the upper arms, the shape where the ball joints bolt up is different, so they take different ball joints. The older type were NLA for a while and are more expensive if you can find them, but there's no problem swapping the later arms onto an older car.