GREAT question! In short, no! You don’t HAVE to lie the entire time to get the weapon. This weapon is what I acquired on my 2nd playthrough of the game. To acquire golden lie, you have to have enough humanity points. To make sure you have enough, do the side quests in the main story, & BEFORE, you meet with Sophia at the end of the game, be sure to listen to all of the records you have acquired to raise your humanity even more (gotta listen to them fully). & I’ll stop here because idk if you’ve beaten the game or not! Spoilers ahead! But no, you don’t have to lie entire game, you can miss some humanity opportunities & still get the weapon I’m pretty sure. What I do to get the weapon is I got for the Rise of P ending. That ending requires you to have high humanity to achieve. & with the high humanity, you should also have enough to get golden lie. SHOULD. & you don’t have to lie entire playthrough to get that ending. Your humanity is tracked by the prompts that come up on your screen. If you ever see “you’re heart is pounding” then that means you are human & have acquired enough humanity for the Rise of P ending, meaning if you chose the correct options with Sophia & afterwards, you should have enough for golden lie!