Graded by NGC as a MS-64. It’s a proof and it’s a FS-901. Unfortunately it has a fingerprint on the obverse.
@Collecting Nut How do you tell the difference between the proof reverse and the regular business strike reverse on these quarters from that era?
Yeah. What’s the big deal about this one? Where are the differences? Or what are the chief “tells?” I don’t know how they know this, quite frankly. I’d sure like to know how they say it happened, too.
It's explained with pictures pretty well here. https://www.cointalk.com/threads/what-did-coinjockey73-find-today.375864/page-15
Type B - Either one of these pickup points are sufficient. (This was called IIb in my original article and RDV - 008 by CONECA) 1) The leaf to the left of the arrowpoints sticks above the arrowpoints in contrast to all other varieties. 2) The gap between E and S of STATES is greater and the tail of the S does not stick up as high above the E in contrast to all other varieties.
From PCGS: The Mint produced Proof Washington Quarters from 1936-1964. Proof Quarters from 1932-1964 did not contain a mint mark. In 1965-1967 the Mint did not produce Proof Washington Quarters. And then in 1968 it began to produce Proof Washington Quarters again, this time the coins had an S mint mark indicating they were struck at the San Francisco Mint. Proof 1969-S Quarters came in really nice quality overall. Examples in Cameo and Deep Cameo can also be acquired with minimal effort. Only in PR68 Deep Cameo condition or higher do they become really scarce. In PR69 Deep Cameo condition they are even scarcer with less than about 100 examples known and none being graded higher.
Thank you for the link. So those reverses were from time to time paired with the business strike obverses, and those are what are referred to as the Type Bs. If I have it right...