Found ... 'smallpox' on another 1932 era coil stamp. EFOCC.ORG published this small article about the 3¢ purple Gilbert Stuart 1932 Wahington coil. The article's concluding line is "Potentially it could exist on other stamps of this era, but I've seen it only on the 3¢ Washington.
Now I found "smallpox" on a #600 3¢ purple Lincoln. Are there other 'smallpox' issues around?
The 'pox' can be seen best on the 2nd image right hand stamp as small dots in the field to the right of Lincoln's head.