Yes, those are how each series was acknowledged, in English, on the book's cover.
In any case, there are those among you (including this very writer) who no doubt sought out and obtained a copy of the book, despite a complete lack of ability to understand anything written in Japanese. And those of you who did may recall that each series was concluded with a short, one-page manga strip drawn by female yonkoma manga artist Yuutarou Kawamoto, whose more famous works include franchises such as Dragon Quest and Ragnarok Online.
This week, #20 of The Reploid Research Lavatory has taken a look back at these manga. And better still, he has translated each one for maximum enjoyment! Now, you can learn such secrets as the reason why Dr. Wily's vehicles contain multiple forms, or who would win in a battle between X and Zero (as brought on by... Iris?!).
You can find the manga for the original series here, X here, D.A.S.H. here, plus those three heroes reflecting during some downtime here, and both Dr. Wily confronting the trio and Tron trying to keep track of how many Servbots she has here.
...of course, all of these are meant to be taken in jest, but they are still a fun treat, nonetheless.