The following narrative, with minor editing, is from my "Silver Dollars & Trade Dollars of the United States: A Complete Encyclopedia" (Wolfeboro, NH: Bowers and Merena Galleries, Inc., 1993)
Numismatic Information
Hoard coins: After the New Orleans Mint ceased business, quantities of silver dollars were shipped to Washington, D.C. and Philadelphia for storage. From vaults in the Treasury Building in Washington, D.C., Uncirculated 1901-O dollars dribbled out onto the market from the early 1930s onward. Prior to that time, the 1901-O in Uncirculated grade was a major rarity, although in the absence of research on the subject few numismatists realized this.
In 1953, a major release occurred, followed by distributions through the mid-1950s. Obtaining coins indirectly from this source, Philip Maul, a Hudson, New York dealer, advertised rolls in The Numismatist in September 1953. In the September 1957 issue of The Numismatist, Harry J. Forman advertised that he had Uncirculated specimens of 1901-O available in quantity. In general, anyone who stocked Uncirculated dollars was apt to have a supply of this date.
Any quantities released in the 1950s paled into insignificance in October 1962, when a long-sealed vault in the Philadelphia Mint was opened, and countless thousands of sparkling, new 1901-O dollars were released.
Circulated grades: Worn 1901-O dollars are common and are of no commercial consequence, as so many Uncirculated coins exist. Many were destroyed in private silver melts of the late 1970s.
Mint State grades: Mint State coins are common, but most are poorly struck and are extensively bagmarked. My estimates follow: MS-60 to 62, 150,000 to 300,000; MS-63, 80,000 to 150,000; MS-64, 30,000 to 60,000; and MS-65 or better, 8,000 to 16,000.
Prooflike coins: Prooflike coins are available.
Thousands exist. While examples are sometimes are seen with cameo contrast, most are weakly struck and/ or bagmarked-not the sort of coin that would attract the connoisseur's eye. On the other hand, John Highfill reports seeing a number of well-struck, pleasing coins. This diversity of opinion indicates that cherrypicking is advised. True DMPL coins and perhaps six or seven times rarer. About 20% of extant DMPL coins grade higher than MS-64.
Varieties
SPACE, SMALL STARS
VAM C-3 REVERSE
Circulation strikes:
1. Breen-5682, VAM-1, 9, 20-22, 24-26, 29-32. Common. The new 3rd edition of VAM lists many more varieties than did earlier versions. If high-resolution optical comparators are ever employed to study Morgan dollar date and mintmark varieties, doubtless many hundreds of discoveries will be made. Now, most VAM numbers pertain to varieties with repunching or some other anomalous feature, not to very minute positional differences. For 1901-O, RW. Julian says 140 reverses were made from both hubs; clearly not all were used.
NEW OVER OLD HUB: DOUBLE OLIVE AT CLAW VAM C-4 OVER C-3 REVERSE
Circulation strikes:
1. C-4 reverse hub over C-3: VAM-3, 12, 14-18, 23, 27, 28. Previously unknown to all but a few specialists, the C-4/C-3 reverse is now plentiful, and the 3rd edition of VAM lists numerous varieties. NEW REVERSE HUB: WIDE NECK/WING SPACE, LARGE STARS
VAM C-4 REVERSE
Circulation strikes:
1. Breen-5683, VAM-2, 4-8, others. Forms the majority of this date; positional and/or repunched varieties. Common Uncirculated.
Dies prepared: Obverse: Unknown; Reverse: 140 (per R.W. Julian).