That picture is the same as my 67 service manual shows, and it's not correct in this case---his idler has a through hole and uses a bolt and nut. the K member "captures" both ends.
Yep that is correct. It came with 2 foam washers which I put on each end of the idler arm where the bolt goes through then stacked the washers on top of the foam washers then installed in in the k frame and put the bolt through.