Justin Bieber took a bling cue from the Kardashian clan -- opting to use their private jeweler to gift himself a super-rare watch that's worth a pretty penny. Sources tell us that the gold watch JB debuted on Instagram Monday -- which he called "a lil wedding gift" for himself -- is actually quite exceptional, in that it's from a rare, vintage luxury line of watches ... with this one retailing somewhere in the 6-figure range. The watch is an Audemars Piguet Royal Oak 5402BA, a line that dates back to the 1970s ... and that isn't really made all that much anymore. Current models of AP Royal Oaks have an average ... (full story)