Justin Bieber and his team are putting the kibosh on stories that the singer displayed his junk in full glory in 2 recent pics.

J.B. fans went nuts over his ... or at least what they thought were his.  Both photos were headless.

Our Bieber sources say it's 100% not him.  We're told Bieber's just laughing it off.  You'll recall, when the naked pic of Bieber in Bora Bora was taken and circulated, his lawyers jumped into action, firing off cease and desist letters.  This time the lawyers are doing nothing, because it's not him.

The tats match, but it's also an easy photoshop and the shading is shady.