Definitely not worth it to restore. Comic restoration is frowned upon and many collectors despise it. That being said, certain OLDER books from the 40s and 50s have restoration as back in the 80s, it was not deemed a terrible thing.
With this book, restoration would kill any value and cost so much it would outweigh the amount you could ever hope to sell the book for (if you ever did). I get that you want it to present well but this book is not all that bad.
6.0 range from me, which is a perfectly good grade to get. Plus, it should still look sharp in a CGC case.