This building stone was found in a field wall near Vindolanda by the Reverend Anthony Hedley prior to 1835 (RIB 1708). It appears to show a boar, and the inscription states the name of the unit: Legio XX V(aleria) V(ictrix).
The stone is now in the museum at Chesters Roman Fort (inv. CH256).
See a building inscription for Legio VI here.