Are old geophysics textbooks useful?
Mathematics and computer science are exact sciences. If something is discovered and known, it is not wrong. With time, there may be better or new ways of doing something, but the old stuff is still correct. This is why you can get a textbook from the 60s and study it. Cauchy's laws are still correct and Euler's theorem is still correct.

This is not the case with earth science (which I expand from your "geophysics"). Just about every paper published in the field of earth science follows the theme of "we thought something but now we found it's actually wrong". And there are hundreds of those per year. While math textbooks teach facts, earth science textbooks present the opinion of the author at the time of writing, which is also commonly the prevailing view in the broader earth science community, but it doesn't have to. In most cases old textbooks are not going to be that bad, but there will be abundant accuracies and omissions. If you go back enough, you might finds that are completely wrong (plate tectonics was only accepted in the 1960s!). But it doesn't have to be this: take subduction zones. The understanding of what happens to slabs once they subduct was only somewhat understood (at least on an undergrad textbook level) in the past 15 years. Whether the slabs themselves melt or not isn't even known today (even though textbooks will mostly say they don't: again, this is the opinion of the author). The inner structure of the earth as understood from seismicity and tomography is being refined every year.

In your textbook links you gave the example of planetary science and volcanism. In the case of planetary science, every time there is a new mission we learn so much. Just example of some discoveries of extraterrestrial volcanoes: Io in 1979, Triton in 1989, and Titan in 2005. Also think of the latest understanding of minor planets, comets and asteroids obtained in the past 5 years. This is not something you will find in even moderately new textbooks.

To sum it up, old earth science textbooks are not completely wrong. But they are wrong to some degree, and they most probably contain a lot of omissions (depends on the exact sub-field). Online sources are usually much better for that. Maybe start with related MOOCs? These can be good starting points. Even if you prefer reading and not watching videos, you can usually find a list of (somewhat) up to date sources there.