I contacted SGC about the 1974 Topps Winfield wrong back, and they asked for front/back images and then replied thusly...
"Hi Elms,
Thanks for the image of the card. It's really appreciated. We would grade this card and mention wrong back on the label. Please let me know if you have any further questions and I'll be happy to help.
Thank you.
Brent Martin
Collector Support"
And now I'm a big fan of their customer service. Two thumbs up.
Edited to add the card in question:
1974winfield456wrongback.jpg