1901 Silver dollars are an interesting coin. It is believed out of the mintage of 6,962,000 as many as 5,000,000 were melted under the 1918 Pittman Act. The rest appear to have been released into circulation, I have never found a reference to any being released in the Treasury Hordes. It has always (since I was a kid) been known as very rare in high end BU. Q David Bowers in his "Guide to Silver Dollars and
Trade dollars" estimated fewer than 225 total in the grades MS63 and above.
1903O is also an interesting coin. Prior to the Treasury release in 1962 of between 200,000 and 350,000 unc coins in $1000 bags, this coin was an extreme rarity. It is believed p to 4,000,000 of the 4,450,000 mintage saw the melt under Pittman. In the 1963
RedBook, which came out before the impact of the teaury release was made known, the 1903O was listed as $1500 in Unc, equal to the 1895 in Proof and surpassing the 1893S ($1200 in Unc) and dwarfing the 1889CC at $275. By 1964 the news was out and the 1964
RedBook lists the 1903O at $30