This is BY FAR the best option.
A) It's called the Tumbler. It's never referred to as the "Batmobile," and that's a generic name that can be used for any Batmobile.
B) Don't call it "Tumbler." It's "The Tumbler." You could call it "Tumbler" if it were a person's name. It's not. It's "The Tumbler." This is a physical object, and it's also a specific copy of a physical object (i.e, not just any Tumbler, it's "The Tumbler")
C) I'm not sure mentioning "1/6" is necessary. But you seem to really want that. In which case, you should call it "1/6 Scale." Just "1/6" isn't enough - it looks unprofessional.
Furthermore, you don't want "1/6" to be on the same line as the name - i.e., not "1/6 Tumbler" or "1/6 The Tumbler." That's awkward. "1/6 Scale" is specific information about the object - it's a modifier giving more detail. In which case, it should be like a sub-title. "The Tumbler" isn't defined by it's 1/6-ness, so it's not critical - which means it should be on the next line.
D) Don't mention the movie it's from - because it's from two different movies. And you don't want to have to mention both, nor do you want to call it "The Nolan Batman Series" or anything, because that's awkward. It's obvious what movie this is from. This obviousness is enhanced by the Bat-logo you're using. It'll probably be enhanced even more by the other objects you'll be displaying nearby.
I could go into more detail, but I think I've made my point. Creecher is right:
The Tumbler
1/6 Scale
is best. (Centered, obviously).
Anything else looks just plain unprofessional - and since you're going to a lot of trouble, I'm going to assume you'd want to do things in the way a museum would do it.