It was marked H. A. Linder.
If my memory serves me correctly, an article came out is Shooting Sportsman on Linder/Lindner doubles. In the article there was pictured was a Linder/Lindner sidelock. The author said something about him knowing of only one other Linder/Lindner Sidelock. A week or so after the magazine came out, it was up on auction at one of the auction houses in the North East. It was purchased. Turned out it was put up for auction by someone at Shooting Sportsman.
Pictures were posted here. Your memory of the discussion serves you well; the consensus being it was spurious.
It was subsequently sold privately to a private party who was aware of the discussion here; reportedly sold again at a Vintage Cup event a few years ago.
The one on Bob Jones' page is not the same one.
