Okay, for the 1 or 2 people who might be interested - an eBay seller says these are from 1971, because he bought a pack from an original owner who wrote the date "1971" on the outside of the pack when he received it. That's the last piece of evidence I need to feel certain these are from 1971 and only 1971.

In case this issue is ever deemed worthy of an entry in the Standard Catalog, or just for posterity, here's a final summary:

1971 F. R. Woods All-Star Photos

Issued by F. R. Woods House of Baseball in 1971. Twelve unnumbered, undated blank-back photos on linen stock, each measuring 4.25" by 7". Came as a set of 12 in packs labeled "All-Star Picture Photo Pak set of 12 photos". Individual values (on eBay) have ranged from $5 to $10 for cards in Excellent or better condition. The complete checklist is:

Aaron
Banks
Bench
Killebrew
Mays
McCovey
Murcer
Powell, Boog
Robinson, Brooks
Seaver
Staub
Yastrzemski