T3 Turkey Reds were produced with 5 distinct card back variations.  
Three varieties in the first series of cabinets (1-50), and two in the
second series (77-126).  
The first back produced by Turkey Red featured a wonderful checklist of 50 of the greatest
ballplayers of the day along with 25 "athletes" or boxers.  Each back provided the collector with
instructions similar to those found on the coupons which were redeemed for the cards themselves.  
In actuality, there are 51 baseball players available with the 1-75 back.  The #28 card, originally
showing Harry McIntyre of Brooklyn was updated very early in the printing and corrected to show
his team designation as Brooklyn now with Chicago Nat'l.  Thus, both versions of the card can be
found with the 1-75 back.

The second back to be produced made an addition to the checklist, noting #76, the great boxing
legend Jack Johnson.  No other changes were made in the series.  There are 50 possible baseball
players available with the 1-76 back,  McIntyre - Brooklyn being unavailable after the 1-75 printing
update.

The final back variation to be produced is sometimes noted as the "No-Ad" back.  A very distinct
and regal looking back variation, the 1-76 checklist remains, however the coupon  redemption
information found on the bottom of the 1-75 and 1-76 backs is now omitted.  All 50 cards should be
found with this back.  I believe these backs were produced without redemption instructions
specifically to reduce the requests for first series cards in preparation for the issuance of the
second series of cards to come.

While most T3 collectors find that completing the basic set of 100 fronts (without variations) is
enough of a challenge, some have taken on the goal of collecting back variations as well.  With
tongue in cheek, I ask you to take pity on this dedicated group.
1-75 Back
1-76 Back
77-126 Back
Ad Back
Second series Turkey Reds were first offered with the checklist back, which showed the T9
boxers (51-76) along with the remaining baseball players numbered 77-126.  The checklist and
redemption information on the back bottom follow the same format as the first series checklist
backs.

Up next was the very attractive Turkey Red advertising back.  In similar strategy to the first series
"No Ad" back, I believe this back version was produced at the end of the premium offer in an
attempt to quell ongoing requests for the cards.  Coupons had certainly ceased being inserted
into Turkey Red cigarette boxes, and so no more coupons, no more checklists and no more
redemption instructions allowed the promotion to slowly wind down.  This back variation has
always been popular with collectors.  Not as rare as most will claim, it is certainly a bit harder to
find than it's second series checklist back partner.  And because second series cards are slightly
more difficult to locate when compared to first series cards, it is a relatively more difficult variation
all in all.

In the second series, variations on the card fronts correlated with variations in the card backs.  
Card #90 noting "Doolan" was found with the 77-126 checklist back, however it's corrected
version noting the spelling as "Doolin" wil be found with an Ad Back.
 UPDATE:  I've recently
located and now own a Dool"an" with the Turkey Red advertising back!

Card #112 noting Paskert - Cincinnati will be found with a checklist back, the updated version
noting Paskert - Cincincnnati and Phila Nat'l will carry the Ad back.

Also card #122 will show Tenney -New York Nat'l with a checklist back and then later, the
updated card noting Tenney - NY and Boston Nat'l will have the Ad Back variation.  
UPDATE:  
I've recently located and now own a Tenney - New York Nat'l with the Turkey Red advertising
back!!

Finally, I believe the #114 card of Bob Rhoades, often noted as one of the most difficult cards in
the set to obtain, will only be found with the checklist back.  This "short print" is an explanation
for the card's relative scarcity.

So, while 50 fronts will be found with the 77-126 checklist back, only 49** will be found with the
Ad Back variety.

** 51 ad backs now, including the Dool"an" and Tenney - New York Nat'l
First Series Backs
No Ad Back
Second Series Backs
  Turkey Red Back Variations