When Harry Winston gave the Hope Diamond to the Smithsonian he sent it down from New York by mail. When the Treasury Department wanted to move 800 pieces of paper two blocks to the Institution they sent it over in care of a guard toting an Uzi submachine gun. This may be a comment on the Postal Service or on our society.

The paper was rare U.S. currency, with a face value of $578,365.79 and a market value that may be even greater, although four of the bills were $100,000 notes that are unspendable and cannot even be shown around by anyone but S. Dillon Ripley and his friends.

Perhaps what made Treasury so nervous was that the money was hot, or at least unlegal. Nowhere in the U.S. Code does it say that the people who print our money can keep samples. They search every shift at the Bureau of Engraving and Printing to make sure they don't. Nevertheless, various Treasury employees have been setting specimens aside ever since the Civil War, for which they have the undying gratitude of Elvira Eliza Clain-Stefanelli, co-curator of the numismatics division of the Museum of History and Technology.

"Our currency collection was very weak, especially in the federal issues," she said . "This Treasury collection is one of the best in the world," said her husband and co-curator, Vladimir Clain-Stefanelli.

Added to the collection of 23,000 bills donated by Chase Manhattan Bank in January, the Treasury series raises the Smithsonian money collection to first rank in the world, although Mrs. Clain-Stefanneli eschews comparisons. "Most collections either concentrate on rarities or aim for completeness," she said. "We have tried for both, because unique specimens are fascinating but having the full runs of issues is necessary for historical research."

The highlight of the Treasury series - although not the most important to scholars - is the $100,000 bill bearing the serial number A 00000001 A, the only one of the unique series that was ever issued.It went on display immediately, replacing the phony $100,000 note Treasury counterfieted for the Smithsonian years ago.

Mrs. Clain-Stefanelli was glad to see the last of the fake one, which was printed on the front side only. "We worked so hard on that exhibit, and then people just skip over everything else to get to that one. I remember particularly a pair of nuns who had their noses pressed against the case, really squashed, just devouring that thing."

Perhaps the Stefanellis have spent so much time studying money as history that they forget that to most of us money is money . "Sometimes I hold a rare old coin and think of how many hands it has passed through, that men may have murdered to possess it . ." Here Mrs. Clain-Stefanelli fell into a reverie from which she was aroused only with difficulty by one of the sherry-sipping VIPs at the presentation ceremony.

Only three of the notes went on display immediately. The rest are kept in a vault that makes Scrooge McDuck's look like a piggy bank.

"I wish our budget would permit us to put much more of our collection on display." Mrs. Clain-Stefanelli said. "But we're very short of money." CAPTION: Picture, GOLD CERTIFICATE, THE ONLY $100,000 NOTE EVER ISSUED AS U.S. CURRENCY, IS NOW AT THE SMITHSONAN - REPLACING THE COUNTERFEIT THAT HAD BEEN IN ITS PLACE.