You wrote: "This is old news, actually.
It first came out one month before he was executed. I believe it was run around the same time they announced boxes had been found that were not presented as evidence."
The Article cited:
"Justice officials said Wednesday the letter was routed to Ashcroft's clerical office in the Maryland suburbs of Washington, where it sat for nearly two months and then was forwarded to the FBI - well after McVeigh was executed."
Boy either you know more information than the Department of Justice or you did not read the article above.