Okay, the back looks a lot like the VOT / X / MVLT / XX.
I think you are correct with the Valentinian II the more I look at it under the loupe. The three letters of the legend on the front that are remaining are rather worn, but I don't think they help much as, if I am reading the site correctly, "AVG" is the last three letters of all the obverses anyway.
What does it mean if it is a barbaric imitation?