Jim,
Thanks, I don't have the vette but I like my 1966 SS Chevelle. Interesting you block is not stamped but that was GM and all GM plants were slightly different with some proceedures. As far as unstamping your block that would have been a no no in the job responsibilities. That guy must have left his shift early or something. Now if you wanted a build sheet. Again, the neighbors of the North AKA Canada GM plant can and does produce those for a mininal fee for cars built there.
cheers
Dwaine