As a boat in the Canadian Shipping Registry, the boat's name must be unique in that registry. Adding a "II" or a "IV" is acceptable as a way of making that name different from another similar name. In all likelihood there was already an "Artful Dodger" registered.Altho, personally, not sure that adding the "II" at the end would be an issue, as the main part of the name is the same. ...
We had a boat called "Phantom V" for the same reason... we simply chose to ignore the "V" except in official paperwork (the Blue Book) and a very subtle "v" on the transom.
I'd agree wtih Marty that no ceremony would be necessary, nor insult or peril risked for simply appending those numbers...