Chuck, 
 
Thing to do is buid it as you want to build it, from whatever is in the box.  Take the instructions (usually required by the rules in most box-stock classes), but also ... take the box.  
 
To really nail it down, take an un-opened Jawbreaker kit along ... if you have one.  Any argument with the judges would be quickly dispelled by cracking open a mint, sealed kit. 
 
Speaking from the experience of years of 'head-judging' that would do it for me! 
 
Good luck! Nice model.