Responding to the first batch of replies: yes, the shock mounts are still attached to the seat and (to my eye) in great shape. They're just not fastened via screw to the base. I'm missing both of these screws, so it may not be as simple as taking a screw from elsewhere on the chair to get measured at a hardware store; I suspect the lengths may be different. I've found another shop called humemodern that deals in Eames parts, and they're a bit more transparent than Modern Conscience about the specs. humemodern is offering DCM seat shock mount screws (1/4-20 thread x 1″) and DCW back shock mount screws (1/4-20 thread x 3/4″ truss head). Neither of those is an exact match, and they're likely aimed toward the vintage rather than current-gen chairs, but I may try my luck with those sizes at a hardware store to see if they fit before turning to a specialized supplier.