1. paraphrasing The Beatles in a Zep thread title = bad form.
2. the actual release date was not on 1/12. First off, 1/12 was a Sunday (albums were never released on Sundays back then). Second, Atlantic Records had already issued a press release stating that the album would be released on 1/20, so there's almost zero chance that they would have jumped the gun. Also, the major music publications (Billboard, Cashbox, etc.) didn't start mentioning the album until 2/1, and it did not hit the Billboard chart until 2/15. Therefore, the album was most likely issued between 1/20 and 2/10 at the latest.