I've got a revised KoboTouch348 plugin working for the Clara BW (running on Calibre 4.12, but should work on 3.48 too). I copied the changes done for Clara 2E from the original
KoboTouch348 but this was not enough, I had to also define BCD. In theory 2E should have need to do this to include 0x401 so not sure why it worked before, there must be another definition somewhere.
I can now use collections and series on both Clara 2E and Clara BW (with latest firmware). Calibre (4.12) also recognised Clara 2E and Clara BW as devices.