No. Of course not. Don’t be absurd. However, this is an actual theory put forth on the Game of Thrones mega-fansite Winter Is Coming, which tops out at 2300 words, and which almost certainly exists solely because the actor that played Benjen and the second guy who played Daario look vaguely alike.
The theory does wisely concede that the Benjen-as-Daario theory doesn’t work for the show, seeing as two similarly bearded yet completely different actors play the roles. The argument sticks to books, detailing all the ways that the two characters don’t completely contradict each other, excluding of course the fact that they act absolutely nothing alike and that the idea is dumb.
Really, I think this boils down to Game of Thrones fans getting a bit stir-crazy after waiting so long for The Winds of Winter and season 6. Just a little bit longer, guys. Hang in there! And please try not to speculate that Varys is two direwolves disguised as a human, OK?