This may be your lucky day. It sounds like you got Syncro 16 rear axles.
Probably worth more than regular ones. Ask on the Syncro list.

Mark

Mark McCulley wrote:
> Turns out the axles and CVs were just the wrong part--the CVs were larger in
> diameter and took larger bolts than the Vanagon ones.
>
> Lesson learned: Don't squirrel away parts unless you're absolutely sure they
> are the correct ones for your application!
>
> -Mark
>