Couple points. The first Authenticast Catalog was produced in 1945. The models sold were likely combinations of models actually produced for war time but never deployed and some that were made post WW2 using the molds made during wartime. Authenticast changed paint colors a little from the comet war time models, and may or may not have the hole completely through the model which is found in the wartime issues.
The lead rot is not seen in all models, either. Just some that have had exposure to something (?) which may have caused it to start. I have seen only a few examples of lead rot, and those were a result of being stored in a wood box which leaches an acid and where there was some dampness in storage. The 1945 models are likely 1945 models which were kept safely.
Photos of Brass masters: