Although there is no right answer, as Tarrintino intentionally left it vague and will not tell what was in his mind when he wrote it, I send to buy the "soul" theory. Also, the combo for the case was "666". When the robber in the coffehouse said, "is that what I think it is?" and Jules said "yes".
Given that it was gold it could have been a "oscar" that Tarintino wanted to win.
Or, Tarintino wanted to mess with everyone, by not telling anyone and leaving it vague.
He did that in Ressevoir Dogs in the final gun fight. The gunshots do not line up. One person gets shot before the gun is fired. Take a look in slow motion. In fact, in the directors commentary, Tarantino said it was the end of the day and he didn't feel like another shoot, so he said that "let's leave it in, and they will be talking about it for 20 years." or something like that.
Given that it was gold it could have been a "oscar" that Tarintino wanted to win.
Or, Tarintino wanted to mess with everyone, by not telling anyone and leaving it vague.
He did that in Ressevoir Dogs in the final gun fight. The gunshots do not line up. One person gets shot before the gun is fired. Take a look in slow motion. In fact, in the directors commentary, Tarantino said it was the end of the day and he didn't feel like another shoot, so he said that "let's leave it in, and they will be talking about it for 20 years." or something like that.