Sure, you can redefine the bounding box for the dataset.
If you define the 3 origin values and the 3 dxyz values,
you have defined the entire grid for the dataset (subject
to its orientation).
Note that in AFNI, the origin location refers to the center
of the voxel at index position (0,0,0). So the origin is at
the corner of the dataset, not at the center. Just to be
clear.
- rick