From studies of single-layer graphene, the authors find that atomic deuteration indeed does lead to reversible chemisorption. However, they find that atomic deuterium treatment of many-layer epitaxially grown graphene on C-face 4H-SiC only affects the surface graphene layer and the buried graphene/SiC interface. Raman and x-ray diffraction experiments reveal that only a small portion of the graphene is affected, showing no interlayer incorporation of deuterium. However, x-ray reflectivity and cross-sectional transmission electron microscopy demonstrate a change of the buried graphene/SiC interface, which resembles a delamination of graphene from the substrate. In some cases, multiple atomic treatments lead to complete delamination of the graphene film.