thank you all, but sorry, my guitar as you can see from the serial number was produced in 2014 and if you take a look at the specifications that Gibson gave in that year, the guitar was equipped with the mini E-tune. http://legacy.gibson.com/Products/Electric-Guitars/2014/SG-Standard.aspx ... probably the guitar could have returned to gibson due to a problem with the auto tune device and they decided to replace them (luckily) with classic tuners ... could it be ??