I would go the reg with the title, and pictures of the vin tag and the one missing on the windshield. Hopefully you can say "at some piont the windshield frame was replaced"- not hacked off. Also, I wouldnt say anything about the frame, and certainly dont say you will not scrape the frame for numbers. You will do what they want or be SOL. The registry likes paperwork and proof (old owner info), so any info you can give them to cover their butts to prove its not stolen will get you further.