[Baltan II]

It's a minor problem in the movie that the book would definitely exacerbate, yeah, because MUTO isn't supposed to be a name but a broad (not even scientific) classification for the kinds of creatures Monarch has encountered over the years. Godzilla himself is simply a MUTO with an existing name, while neither Muto gets its own distinct name in the final movie.

They did in the leaked movie script, Hokmuto and Femuto, but the male's name makes zero sense now since he never attacked Hokkaido and Femuto is dumb.