Imperial shooter?

Hey guys, can anyone help me with this. I am building a matching unnumbered Imperial proofed shooter with armour replacement parts. I am short a few parts like a holdopen, a trigger, a center toggle, a locking bolt and lastly a barrel all unnumbered and proofed only. The barrel is what concerns me. Does anyone know of one unnumbered and only proofed, was there such a thing made and would anyone be able to help me. Mr.Tom Heller my trusted parts man has never seen a barrel like this, would anyone else have any suggestions on the barrel? The other parts I am missing I feel confident will show up someday.