After waiting many months for a backorder, I called Sears and chatted with Delaney. She said she'd look into it. Amazingly it showed up in a couple of days. I thank Delaney.
However, I quickly discovered that the design has been changed. Huge problem. The two holes in the cross brace WERE 11 cm apart. Now they are 14 cm apart. This is bad. The holes are supposed to line up with the threaded aluminum sleeves imbedded in the upholstered wooden backrest. I have only two options. 1) Abandon the bolt/sleeves, buy 2 wood screws of the correct size and hope that they work over time. 2) Take the seat to a re-upholsterer to have them redo the seat. I'm gonna try option 1. If the screws don't last, I'll probably have to come back later for option 2.