Can someone identify the font that is used in INDEX I of RTK1?

Is it available anywhere?

The closest I could find was the EPSON 教科書体Ｍ font
http://www.wazu.jp/gallery/Fonts_Japanese.html

This font works in MS Word but it prints out an incorrect character for the Kanji "orders" (Frame #1401), and all Kanji characters that contain it as a primitive. (Is there a workaround for this?)

According to the PDF, it's "SN", with variants "SN-AA", "SN-T" and "SN-W". Not very helpful I know, but maybe you can find some clue on Google.

Font? It's hand-drawn.

From the acknowledgements: "Furuhashi Mine 古橋実根　penned the characters in the text and Indexes".

"I find that it works just fine in Microsoft Word"

Have a look at http://www.wazu.jp/temp/EPSON.gif

Oops. Microsoft Word did not use the word correctly, and defaulted to Mincho.

I now see what you mean with the "hand-drawn font" version of the character.