True, no Snubber mount, though you can machine (or have a shop machine) flats and drill / tap the 3-mounting holes to allow normal pinion snubber mounting. Dr. Diff has converted them in this way.

http://www.doctordiff.com/drivetrain/dana-60/#ty%3Bpagination_contents%3B%2Fdrivetrain%2Fdana-60%2Fpage-3%2F

Another option, is to mount an adjustable pinion snubber to the strike/reinforcement plate on the underside of the body above the differential, then the bump-stop contacts the upper side of the differential housing performing the same function.