Your findings seem correct to me. The Oberkocken lens serial number of the lens indicates early post war production, and some camera parts were made in Dresden, that ended up in the Soviet Occupation Zone in 1945, and it makes sense that the Stuttgart factory used up the pre-war parts they had. They also started redesigning the camera to what became the Super Ikonta III and IV.
Is your Tessar coated or uncoated? Some of the earliest post-war Oberkocken lenses were uncoated.