I've seen this some models. The exposed nut rear caliper was used to facilitate the mounting of the rear reflector to the brake bridge. The front reflector was mounted under the headset locknut. While it would have made sense to use a fork with an exposed brake mounting nut, this may not have been possible. Lawee likely selected a stock Tange fork as a cost concession. To get the level and/or style of fork they wanted, they may have had to accept a recessed mounting.