Lee Harvey Oswald's Final Uncashed Paycheck, Up for Auction

Lee Harvey Oswald -- the man some believe acted alone in assassinating President John F. Kennedy -- never cashed his final paycheck ... on account of being dead, we're assuming.

Oswald's check from the Texas School Book Depository is now up for auction ... and it's likely to fetch a lot more money than what it was originally worth to him.

It was issued to Oswald on December 3, 1963 -- 11 days after he killed JFK, and 9 days after he was shot and killed by Jack Ruby.

As you can see, it's handwritten other than the stamped amount of "$43 and 37 cts" and includes a note at the bottom left that reads, "4 Days. Lee Harvey Oswald for Nov '63."

This implies he was paid for 4 days that week, but not a fifth day ... possibly Friday, November 22, the date of the assassination. Of course, Oswald was seen working at the book depository that morning ... before climbing into a 6th-floor window, and taking aim at Kennedy's motorcade in Daley Plaza.

Oswald fired 3 shots at 12:30 PM.

The check ended up in the possession of Marina Oswald's lawyer, John Thorne. He apparently paid Lee's wife the cash in order to keep the check, which he obviously realized would become historic memorabilia.

When Thorne died, it was transferred to his widow ... who's passed it along to Heritage Auctions to put it on the block. We're told it could haul in thousands, as it's comparable to checks signed by John Wilkes Booth ... which can sell for up to $10k.