All un-marked transformers are made by Tamura.
"Special" notes by the transformers means they are personally made for Sakuma.
Unfortunately, Tamura has no plan to make them again, and Tamura does not accept personal "special" orders, either.
"PC-3004 Special" is a part number in the Sun Audio. It is not a part made for Sakuma personally.
On the schematics, there are some specification omissions pertaining to the primary or secondary of transformers.
Please visit the Tamura pages on this web site to identify more details about these transformers.
For example, the parallel connections in the secondary are omitted as shown in figure 1.