I started a new game, when I meet up with Newboy after escaping the dungeons, he still does not give me the amulet, I also tried killing him and looting his corpse but he does not have it in his possession. Anyone running into similar issue?

Why the hell would you kill that poor boy?

Right at the start of the Prologue, after exiting the tent and Triss's affections, you meet him and his buddies in the camp. You have to convince him that the amulet he has is magic, but will not protect him in battle.

Only then, will he give you the amulet after you emerge from the dungeons.

it's been said more than once. You can receive the amulet as soon as you start the game in the camp when you are asked about the amulet you can check it, and say it maybe brings bad luck. After that you can get the amulet at that moment and not have to wait to have it after escaping the dungeon

Maybe I should be more specific, this is my second play through, the first time I completed the quest, but only with the installation of the mod/fix.

This time around I told him that the amulet is cursed, but he still never gave it to me, or at least it's not in my quest items inventory. When I meet him after leaving the dungeon, still did not get it. Killing him also did not yield the amulet.

Strange. I always got the amulet right at the beginning. He doesn't have it any more when you meet him after you escape the dungeon.

When I first met him in camp I told him it is magic but it will not help him in combat.

Then I met him when I exited the dungeon and he decided to help me by distracting the guards, but I spent too much time looting the nearby bushes and stuff (:D) and he and the guards attacked me. After I killed them all, I picked up the amulet from his body. (or maybe he gave it to me before going to distract the guards, I am not sure now :D)
This was all still on 1.1

the way to get the medallion at the camp is not to tell him that it won't be usefull in combat.

There's a third option there to check the medallion and tell them it brings bad luck to the wearer. Then the group will thank geralt and ask him if he wants the medallion.