In my case, after failing to find a way to positively ID the chassis, I simply presented my purchase reciept for the bulk of the parts that comprised the bulk of the car...they called these "components" and categorized the car as scratch-built.
But, since there was significant evidence that the car was a West Coast Cobra, they put WCC as "model" in my title/reg paperwork. However, they refused to use the WCC number I located as the VIN, since the evidence of said number couldn't be seen anywhere other than the impressions on a yellowed slip of paper...with no matching numbers anywhere on the car. So, they sent me to the CHP. The CHP will assign a VIN number once the car is roadworthy, stamp that number onto a VIN plate, and rivet that vin plate to the frame.
I left out a few things. First, the car came with 5 yellowed books labeled "Stallion". Each book was labeled (with black marker) "Engine", "Chassis", "Suspension", and so on and contain a mixture of hand-written and type-written instructions, as well as many photo-copies from other sources such as Ford manuals for the common sub-components. Inside these books, many references were made to both "Stallion" and "West Coast Cobra". In one of the books, what we believe may have been the original MSO was found; which appeared to have been duplicated on a mimograph machine. One side was legible and looked like the instructions for how to fill out the other side. Unfortunately, the other side was completely bleached white. At the top of this form, you could make out an impression of a WCC-XXXX number, which I carefully recorded. Along with this, I other original paperwork was found pertaining to the purchase from a long-defunct West Coast dealer in the Los Angeles area, as well as the original purchase price information, etc.
Through my searching I found Vern at West Coast Cobra, who informed me that the WCC number I found one one of the documents sounds legitimate, but he couldn't help me cross it or confirm it. He did say, however, that if it was a West Coast Cobra, this number would be stamped into a frame rail. I've been over every inch of this chassis. It simply isn't there. It's possible that it was welded-over by the original owner. I've learned that there are additional structual members added to this chassis by that owner; so perhaps it is under one of those members or destroyed by a weld. I don't know...and I'm not about to tear the frame down to find it, so it will remain a mystery. I'm content enough with the information I have...It's most likely a 1981 West Coast Cobra. There are doubts, however. I've sent pictures to Vern on multiple occasions asking questions about various fitment issues such as the pedal assembly, and he has replied stating "That's not West Coast stuff...". So, I guess I really don't know what I have. Whatever it is; it's fine with me. I'm making it my own anyhow.
Byron