Good buy. I got my first Lyman manual, # 43, new, in '65 when I started this delightful hobby activity.
You will get a good bit of data for powders that are no longer available, HiVel2, BLc-2, etc., but the rest of the info is as good now as it was then. I don't agree that powders, or anything else, is "different" today. As the book clearly says, start with the low charges and only work up if no over pressure signs appear. That precaution remains as true today today as it was in '65.
The last pages in the older Lyman books were, usually, shotshell data and ALL of that info is too dated to be valid today. I mean, many of you young whipper-snappers have never even SEEN a paper hull shotshell, much less reloaded one!
So, if it's water damaged back there you really haven't lost much, except some history.