Yep, believe everything inside of the if n == <blah> can be swapped around without issue. I actually originally started with encoder 2 and 3, but found that my left hand was always covering the screen on my stock Norns, so ending up switching.
FWIW, I’ve been told the encoder 1 and 2 layout is a bit odd for shields. I’m wondering if a param or a simple boolean flag users can edit (use_shield_encoder_layout) would be a good idea. Will look into it for the next update!