Yes, there is a small rubber bumper that goes there; my '69 RR still has them. They have a long "tail", similar to glovebox door bumpers, and a flat upper contact surface. You might find them at a good hardware store that has the fastener & etc drawers.
If they look like the ones in the attached pic, Ace Hardware has very similar ones that should do the trick. I've never found a part number for them, ePay sellers have them for several bucks listed as ashtray stops.
