1 Attachment(s)
Front window guide rollers
The parts book shows the rollers were supplied as part of the guide plate, item 13, in the attached drawing. The early type had two rollers on each plate and was superceded by the single roller type. If yours had two rollers per door, the second one farther down in the channel might still be giving partial window support. Indications are GM did not supply these rollers as a separate part. The part number for the RH plate is 7682222, with the LH part being 7682223. The official name is Plate, front door window lower sash channel guide.
The 9711820 rollers used on the rear windows are removable as a nylon roller mounted on a threaded stud. These are still available and may be the ones showing up on eBay.
The guide plates are the same on 1967-68 GM B & C body 2-doors with a few exceptions: 67-68 Pontiac Grand Prix and 68 Chevrolet Caprice. Those cars did not have front ventilator windows and use a different mechanism. The Chev and Pontiac 2-dr sedans are different and use the 4-dr sedan mechanism.