Thank you all for the replies. The item in question isn't actually Hitler's watch, but it is associated with him in some way. It is a McGuffin in a way because it only serves to move the plot forward and no other real significance. Unlike the Rabbit's Foot or Marcellus Wallace's briefcase, the item is identified. The item (a ring actually) belongs to a very bad man, and the protagonist steals it without knowing it belongs to him. The fact that it belonged to Hitler only makes it valuable and nothing else.
On a side note, I've been thinking a lot about this story and I am thinking of making some drastic changes, the first being changing the entire thing to first-person. I prefer the mystery of the protagonist (and the reader) not knowing who is after him. I think in this case it makes for better drama. Luckily, I've only written eight chapters and not 80k words.
Okay, I can't hold it in any longer. It's the wedding ring he gave to Eva Braun in the bunker. I've looked around, and I'm pretty sure no such ring exists. Whew, glad to have that off my chest lol