Thanks for the information.
Why would a photographer prefer a 35mm on an M3 with goggles instead of a 35mm on an M2 or an M4 without goggles?
A Google search turned up one description of the Kong Leica as a U.S. military version called a KE-7A. However, since this military version is an M4 and the M4 has 35mm frame lines, goggles would be unnecessary.