So I'm to blame as well, I didn't notice the problem at all :-(. Thanks for noticing and fixing it.
The changes look good to me. I went through the code and I _believe_ that's all that needs to get updated.
I was also wondering about `prefs_kb_search_name()` which works on top of the filtered model now. It is used to locate the plugin keybindings from the list when pressing Keybindings in the plugin manager. But since the filter entry is cleared when the Properties dialog appears, it locates the plugin alright despite working on the filtered model.