They're allowed to use that old logo. They were probably selling that replica BEFORE Cody brought that design back and didn't feel it necessary to make a different one with the WWE logo on it.
http://www.wweshop.com/item/wwe-classic-tag-team-replica-belt/TitleBelts/06-01408
These belts also have the old WWF logo on them, although they actually use "WWF" in the description here which actually is a big no-no.
Someone alert the panda.
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Thank you, Eddie Guerrero.
http://www.wwe.com/f/styles/photo_large/public/photo/image/2012/04/WM28_Photo_255.jpg