So the ZIllion weapon came first before the Sega Light Phaser or was the Light Phaser based on something else?
Yeah, Zillion debuted in April 1987 several months after Light Phaser was released, so more likely that the Zillion design was borrowed from Sega.
Every console had their gun peripheral back then (Nintendo's NES with Zapper and Atari's 7800 with XG-1).