Hardly. (Destiny)

by CyberKN , Oh no, Destiny 2 is bad, Wednesday, April 22, 2015, 14:58 (3344 days ago) @ Cody Miller

The Vex Mythoclast will not be bumped up to 331 Attack.

The Vex Mythoclast (while branded as an Exotic) is bound as a reward to the Vault of Glass. Thus, it shall be frozen in time. I cannot predict the future. For now, it will remain as it is… the most dreaded gun in PVP.

On the topic of Legendary VoG weapons,

[331 Attack is] only for Exotics. Our Visions of Confluences are still frozen in time. I love that gun, too. I’ll continue to beg for future solutions.

Source: http://planetdestiny.com/vex-mythoclast-max-attack/