New pictures posted. I rubbed and fine sanded for a couple hours. I didn't discover any other markings. I'm still of the thinking that it's the original block. And I agree with 165th's logic of why would someone restamp an incorrect # on the block. It's probably doesn’t matter at this point since the owner didn't accept my offer. I'm certainly not comfortable upping my offer since I am reluctant to own another "storied" car anyway. Thanks everyone again for all the expert input...much appreciated.
http://s1115.photobucket.com/albums/...rotter54/70TA/