It sounds like you may be mixing up form 1 with form 3, which is used just for NFA firearm transfers between SOT holders. An SOT holder would only be receiving an SBS from Tromix if they (not you) ordered it from Tromix. In that case Tromix would just use a regular Saiga 12 shotgun from their own stock to make the SBS, and then the SBS would be transferred from Tromix to the other SOT holder through a form 3 (an individual purchasing the SBS from this SOT holder would then go through the NFA transfer process using a form 4). In your case though it is you, not Tromix, who is the owner of the Sa