It is probably too late to get the desired paper stock and cover finish for my book, as it’s already with the printer. However, I have been trying all year to find out the specs for any of a handful of titles that I particularly admire. This has become an obsession.
My book designer and printer can’t help. The authors of the books I like don’t know, either. When I pick up a book that just feels welcoming (e.g., The Art of Racing in the Rain), how do I find somebody who can tell me what makes it different?
Your book designer should know about cover stock and finishes. If they don’t, that’s sad. Your book printer should also know about cover stock and finishes. If they don’t, that’s sad.
Now, they would have to see the actual book to be able to tell you. And it might still be an estimate in some cases. But most people in the book design and book printing business can tell you what stock was used (at least in general terms). The only person who would know for sure about the specific brand name of the paper stock would be the printer of that book and possibly the publisher.
The finish for a book is generally matte or gloss finish applied as a UV varnish or a film lamination. Again, those are the general terms. There could be specific brand name finishes beyond that. Again, the book printer or publisher for that specific book should know what was used.
Since the specific title you referred to above was published in hardcover, softcover, and mass-market versions, I presume your question concerned the trade paperback (aka softcover or quality paperback) version. The hardcover would generally have a jacket and mass-market paperbacks might use embossing techniques but rarely rely on special cover stocks or finishes.
If you really need the answer, ask the printer (if you can locate them, which will be tough) or ask the publisher. Book authors rarely know these technical details if they are published by a larger publisher.