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
Commentary: The 1902 Philadelphia Mint dollar was the first issue employing the C-4 reverse on all dies. Interesting varieties are those from a reverse die made by impressing the new C-4 hub over the old C-3, and distinguished by having the "2 Olive Reverse." Of course, these over-hubs exist for other, earlier dates as well, and for certain later issues through 1904. Credit goes to Leroy C. Van Allen and A. George Mallis for coordinating and distilling the research efforts of many enthusiasts in the field. Years ago, no one knew about the over-hub issues.
Hoard coins: Like a number of other Philadelphia Mint Morgan dollars, the 1902 in Mint State was elusive before the 1930s. Demand for high grade specimens of the date was answered by Proofs. Circa 1947-1948, the Treasury paid out bags of 1902 dollars, but still they remained somewhat scarce. In the early 1950s, additional quantities were paid out, and in the closing years of the decade, many bags came to light. Today, probably well over 100,000 Mint State coins exist.
Circulated grades: Low grade 1902 dollars are common. At the higher end of the scale, numerous sliders exist; AU coins that are sometimes sold at bargain prices as "Uncirculated."
Mint State grades: Mint State coins are relatively plentiful from Treasury releases, although this is not one of the more common dates. Most surviving Uncirculated 1902 dollars are in lower ranges such as MS-60 through 62 and 63. MS-65 coins are quite scarce, relatively speaking. Estimated population: MS-60 to 62, 80,000 to 160,000; MS-63, 20,000 to 35,000; MS-64, 15,000 to 30,000; MS-65 or better, 5,000 to 10,000.
Most Uncirculated dollars of this date are satiny rather than deeply frosty. Striking varies from poor to sharp. Once again, cherrypicking will pay dividends. Bagmarks, when seen, are apt to be light and widely scattered.
Prooflike coins: Prooflike coins are elusive, and probably fewer than 1,000 exist. Most have low contrast and are rather unappealing. DMPL coins are rarer yet.
Varieties
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: Breen-5689, VAM 6-11. Publicized only relatively recently, the variety is probably plentiful, but most 1902 dollars have not been inspected for this feature.
NEW REVERSE HUB: WIDE NECK/WING SPACE, LARGE STARS
VAM C-4 REVERSE
Circulation strikes:
1. Breen-5688, V AM 1-5, positional varieties. V AM-4 has doubled die obverse, with doubling on Liberty's ear, nose, lips, and chin; rare. Not all the 80 obverses, 67 reverses were used. Common.
Estimated quantity melted: Many under the Pittman Act and later authorizations, but the minority probably went into circulation. Availability of prooflike coins: Prooflike coins are very scarce. Most have unsatisfactory surfaces.
Characteristics of striking: Ranges from poor to sharp, but most are average or above average.
Known hoards of Mint State coins: Large quantities were released by the Treasury, especially in the late 1950s.
Commentary
The 1902 is common in lower Mint State levels but is quite elusive MS-65