The first book was written sometime in the nineties. I believe it lists all of the TMNT merchandise made at that time, including prices. Don't know what else it contains, but I've been wanting to buy it myself.
The second book you listed is a guide for the TMNT table top RPG. If you're into those kinds of games, then you should pick it up. From what I've heard, it's actually a lot of fun.
Hope that helps. I'm sure other members who own the books can provide more detailed info.
