I haven't managed to get my hands on an original to confirm one way or another, but regardless it does make more sense for the blue LED / zener diodes to be in opposing orientation.
Desoldering an LED can be tricky, it'd be easier to just reverse D4 and D5.
The PCBs have been updated but there are still a few floating around with the older layout. Install D4/D5 in the orientation shown in the current build doc, regardless of the silkscreen on the PCB.