I ordered the 40º x 3/16" carbide dovetail cutter today...actually cheaper than listed on the web site...If anyone else is interested, they do not sell directly, only through their distributors...You can find the closest one on their site...and CC order from the dist...
FWIW, back in '69 when I worked for Twin Industries Inc (an aerospace subcontractor) dovetails were cut by a pieplate-shaped cutter on a horizontal mill...the workpiece was clamped at the desired angle, and one side of the dovetail cut...then the piece was rotated and the opposite side cut...
Something like this...I don't know if that is how the Luger was done, but it is a quicker and safer method than a teeny tiny dovetail cutter...