If its not original, its not original, end of story. Dated parts on some mongrel block don't add enough value to the car to justify the search and expense of adding them to a NOM engine. As far as regular production enignes go, L48's,L30's, LF7's, L65's etc. my own personal view is you won't get one cent more from me, for a dated non original block and components than you would for a 1974 truck block with "correct looking" but maybe not dated correctly parts on it. Once the original is gone, it really doesn't matter whats in there. Same goes for a CE block without paperwork. Theres far to many of those floating around to say it was installed at the dealer in 1969 to justify any added value. If you have paper, then thats a different story. You may be able to get more money for correctly dated stuff and CE bloclks on the lower production motors like L34's, L78's, Z's and COPOs but not for the other engines, but still not enough to offset the value of the parts you need to make it "correct".