Here are the IPMS Nationals rules: OUT-OF-THE-BOX entries will be governed by the following rules:
A. KITS. Any commercially available kit may be used. The number of categories incorporating Out-Of-The-Box awards will be determined by the host chapter and the National Contest Committee.
B. FINISH. All finishing techniques are allowed. Decals other than those included with the kit may be used. Insignia, markings, and instrument panels may be hand-painted instead of decaled. Weathering is permitted.
C. CONSTRUCTION. The modeler may fill seams and gaps; sand off rivets; drill out gun ports, exhaust pipes, or other appropriate openings; thin to scale such parts as trailing edges, flaps, and doors; add rigging and antennas; and add simple tape or decal seat belts in the cockpit of an aircraft or the interior of a vehicle (NO commercial or modeler manufactured hardware - e.g., buckles, etc.).
D. IT IS NOT PERMITTED TO: vacuform, manufacture, or replace any part, or substitute parts from another kit; cut or separate canopies, surfaces, hatches, doors, etc. (no major surgery); combine a standard kit with a conversion kit; add anything other than specified on the instruction sheet except as shown in Section C above.
E. INSTRUCTION SHEETS. Modelers must attach the kit instruction sheet to the entry form. Models entered without an attached kit instruction sheet will not be considered for an Out-of-the-Box award.B: