HIN decoding/location for 1977 26' Santa Cruz

[palfvin]

I can't find the external HIN plate on my 1977 26' Santa Cruz. It may have been removed when I had the gelcoat redone on the transom. Is there an internal location for the HIN as well?

On a related point, all of the documentation I have on the boat reflects a 14-character HIN rather than a 12 character HIN, with the difference being that the date of certification is represented as a two digit month followed by two digit year rather than the standard 1 character month (A-L) and the last digit of the year. Specifically, I have: CDR56281067777 instead of CDR56281F777.

This matters because I've received a notice from the California DMV saying that I my HIN does not confirm to US regulations and as such, is considered invalid and my registration subject to cancellation.

I'm going to call the DMV, but I'd like to be able to reference something that documents this format or Carver's exception to it. I found this online which mentions some boats having a four digit certification date, but not both a four digit certification date and a two digit model year. https://www.usps.org/national/safety/HIN/HIN.pdf

Does anyone else have a 14-character HIN on their Carver?