According to
KISS | Gene Simmons | LoBue custom bass the whereabout of the Lobue is surrounded in mystery:
"Exactly what happens to the LoBue is matter of some confusion. In 1978 Gene recalled that: "[I used that bass] For about four years, until one night I threw it to my roadie. At the end of our show
walk offstage and I throw the guitar off the stage, and everyone gasps. That one night he dropped it and the neck broke in half." [*] Spiro of tribute band fame has mentioned that Gene told him it was stolen while being away for repairs after Gene "fell off the front of the stage". Gene had another story in 1996: "A couple of years later I lent it to Micki Free, whose band Smokehouse opened for us once, and never saw it again." In a 2013 interview at G-Club in Tokyo Gene threw another wrinkle to the story of the LoBue's demise, this time suggesting that he used the bass on stage in 1982 when he fell off the front of the stage, cracked the neck and promptly gave the pieces to a member of the audience.
Seeing how Gene is, shall we say, slightly inconsistent and prone to exaggeration methinks it's best to take the word of one of the participants of one of the stories. According to Micki Free the story is true that Gene lent him the bass and that it was subsequently stolen while in his posession."
So maybe the neck was broken and maybe the bass was stolen... Only Gene knows...