Why yes, it appears he is:
Bishops will do that, from time to time—these days, it’s not an uncommon practice at diaconate ordinations—as a sign of the bishop’s connection to the order of deacon.
It’s debatable, though, whether they dressed like that in the 4th century. (And let’s not even get into the question of whether the fellow pictured actually drove the snakes from Ireland…)
Anyway: you see the above image, or variations of it, very often. In fact, a version of it hangs in the lobby of the building where I work, in a city where St. Patrick’s Day is almost as important and sacred an occasion as Christmas.
Happy St. Patrick’s Day!