Do you have the hull number of your Corbin please ?
If it is from 1979 my guesses are #7, 15, 19, 20, 27, 29, 33, 34, 39, 40. Many of those were finished but it is a process of elimination to identify the unfinished ones.
The full hull stamp will be something like "ZCJ000010179" and will be on the stern, high up near the cap rail.
I am trying to complete the file I have on all of them.