OK, I need to look for another number in the same stamped location that refers to the vin code. This number indicates that it was assembled at the Tonowanda factory (T) on Dec (12) 23rd (23) and we already established what the TKB stands for. I found a site that lists this and shows an example. I'll try to upload the photo and post it.
I'll try to see if I can uncover this number from the block now.