Yeah, they are. As I recall, the original launchers had a round hole, while the reissue one had the groove we know from modern launchers. I believe if you cut out the plastic for the groove on the reissue launchers, the original missiles can fit and be fired.

FFN means Fit For Natalie (as in Natalie Portman, the actress). Since I am no longer a fan of hers (yet everybody knows me by this screename), I prefer to be called FFN.