The agreement should have the license # of the inspector, the fee for the inspection, the standards of practice used, and explain the limitations & scope of the inspection. For a sample of my agreement go to http://www.greenshomedesign.com/9810.pdf.
Do I recommend signing up? Sure, if what he offers is what you want. I also believe but really can't say, since I have not seen the agreement, that it will also state the limits of his liability, should something come up later. You may wish to think about that one but, unless you're willing to pay for a ton of his insurance (errors and omissions,) you may find this to be a good way to reach a complete understanding.
As for signing, I dunno, why not?