... usually not, but if the balls the clip hooks onto are corroded/rusted, then it won't be as tight as it REALLY should be if the balls were brand new, it won't do any harm... it's just a personal preference of mine that I wanted to share, but you shouldn't have to.
Not sure about the differences between front/back/activa roll one.... just ask for the rear heigh corrector plastic clip, it's quite common for it to fail and they will know what you are on about.