This was Dorman's first cap for his country, having previously been an unused sub in two friendlies. He only became available for Wales a few months ago thanks to a rule change allowing players to play for a country if their only connection was having gone to school there for five years or more. Wales had a number of injury problems, so Dorman was able to start the game.
By my reckoning, the last Saint to win a full cap would be Paul Fenwick when he played for Canada in the mid-90s. Other players, such as Paul Gallacher and Paul McKnight, have been called up by their countries while playing for Saints since Fenwick graced the international stage, but they haven't made it as far as the pitch.