For a few months spanning 1916 and early 1917, the half dollar wore its mintmark on the front, tucked under IN GOD WE TRUST, and then the Mint moved it to the reverse for the next thirty years. Because the change came mid-year, 1917 exists as four separately counted branch-mint issues, and this is Denver's scarce one: 765,400 obverse-mintmark coins against 1,940,000 with the mark on the back.
These are counted varieties in the fullest sense, official figures for each striking, which puts them on the pleasant side of the doctrine this site's fourth article laid out: the record already did the counting, so the buyer's only job is attribution. Flip the coin; the front tells you which mintage you are holding.
A two-and-a-half-times scarcity gap between two versions of the same date and mint is exactly the arithmetic that invites alteration: reverse-mintmark coins reworked to pass as obverse strikes. The mintmark's location is the attribution; its surface is the authentication.
| Issue | Mint | Mintage |
|---|---|---|
| 1917 Walking Liberty Half Dollar | Philadelphia | 12,292,000 |
| 1917-S Walking Liberty Half Dollar (Obverse Mintmark) | San Francisco | 952,000 |
| 1917-S Walking Liberty Half Dollar (Reverse Mintmark) | San Francisco | 5,554,000 |
| 1917-D Walking Liberty Half Dollar (Obverse Mintmark) | Denver | 765,400 |
| 1917-D Walking Liberty Half Dollar (Reverse Mintmark) | Denver | 1,940,000 |
Mintage figures: United States Mint (Annual Report of the Director of the Mint), Royal Canadian Mint records, and — for the 1935 banknote issue — Bank of Canada printage records as published in the Charlton Standard Catalogue of Canadian Government Paper Money, cross-checked across independent published references. Specifications: United States Mint coin specifications.