Mornin,Kevin.
Yes.
Depending on the organization,you may use green leaf lettuce,parsley,and cilantro as garnish-if you choose.
Some others allow meat only,with the rule that there be 6 or 8 or more separately,identifiable pieces.
The feeling about pulled pork would be to place plenty in the box and there would easily be that many "portions".
Some organizations allow you to sauce or not,and it is judged as presented.
Memphis in May allows two sauce containers[they may contain any combination of sauces,rubs,marinades,or basting sauces] with the turn in box.
The judge will first taste the meat, then will select the sauce they feel best compliments the meat and judge them together.
A bad sauce could bring down a good meat score.
Folks out near Kansas like to present some slices on top of pulled pork.
The Carolinas' group is partial to finely pulled pork.
The south likes bite size chunks.
Some of the MIM shoulder cooks will separate out attractive muscle sections.
Many like to include nice bites of bark,so that the judge can taste inside and outside meat.
Some season or add sauce to the pork and some don't.
Simple huh?
No, a bun would not be allowed in main categories,but could be in the box for an ancillary event.
I have included a couple of sites that are from the bbq forum that asks the members,typically judges and cooks,to score the boxes.
Juggy's SurveysMore Juggy's SurveysThese are from actual KCBS presentation boxes from forum members.