Hi jy6537,
Those books are perfectly fine to use during your studies - since the content and patterns behind the GMAT are essentially the same as they were back in 2016. That having been said, the TEST itself has gone through some changes. Earlier this year, the Quant and Verbal sections were both shortened (in terms of number of questions per section and total time per section), so you will have to account for those differences during your studies.
Since you've been away from the GMAT for the last couple of years, it would be a good idea to start off by taking a FULL-LENGTH practice CAT Test; you can take 2 for free at
www.mba.com (and they come with some additional practice materials). That score will give us a good sense of your current strengths and weaknesses (including what you may have retained from your prior studies) and will help provide a basis for comparison as you continue to study. A FULL CAT takes about 3.5 hours to complete, so make sure that you've set aside enough time to take it in one sitting. Once you have those scores, you should report back here and we can come up with a study plan.
I'd like to know a bit more about your timeline and goals:
1) What is your goal score?
2) When are you planning to take the GMAT?
3) When are you planning to apply to Business School?
GMAT assassins aren't born, they're made,
Rich