My KYB rear shocks didn't come with bushings either. I had them installed on the car for about 5,000 miles that way and had no problems. If you're still concerned about it, see if there are some universal bushings or something intended for another application that will fit, and use that. Again, installing them that way will not damage either the shocks or your suspension.
'07 Toyota FJ Cruiser
(Sold)1997 Lincoln Mark VIII LSC Black/Black
Chrome Cobra R's, BFG Rubber, Cobra/KVR Brakes
Custom Koni front air struts, Bilstein/Addco in rear
Cobra Intake Manifold, SCT XCal by Lonnie of BOC