Firstly, you should only have a pauldron if you're a TD (sandtrooper) or a HWT (heavy weapons trooper) or one of the EU derivatives. Personally, I'm not keen on pauldrons for TK's as that's not in the films, but to each their own.
In regards to decals or personalized gear, it's a garrison to garrison policy. In my garrison, there's a policy of "decorate as you like" for non canon events, but for canon events like LFL or hospital visits, etc. it's formal only.