A simple SEARCH would answer a lot of your T206 questions. Here is a link on this subject......
http://www.net54baseball.com/showthr...nt+460+factory
3a. Approx. when were they printed?
In early 1911.
3. What series are they found in?
The PIEDMONT 460 factory 42 backs exist on 60 of the cards in the 350/460 series.
AND, on the following 12 cards in the 460-only series......
Chance (bat)
Chase (Trophy)
Devore
Kleinow (Boston)
Latham
Murray (portrait)
Overall (blue sky)
Schlei (portrait)
Schaefer (Washington)
Seymour (portrait)
Smith (Boston & Chicago)
Wiltse (portrait-cap)
5. Is there other backs that were printed in Fact.42?
AMERICAN BEAUTY 460 factory 42
SWEET CAPORAL 460 factory 42 (overprint)
SWEET CAPORAL 460 factory 42
TED Z