A couple of sources to consider........
http://ls6registry.com/tech/trivia.htm
http://www.chevelles.com/forums/15-t...h-factory.html
Mid year for the LS5 in Chevelles seems early to me. Also the LS5 Convertible with a 10D date is certainly the earliest I've seen reported. Owned one as well and I thought it was one of the earliest with a 12C production.......still have a copy of the original build sheet.