How to identify turkey liver
Here is a great place to go to compare identified inards with what you have.  

http://www.eatmedaily.com/2009/11/offal-of-the-week-turkey-offal/

Personally, when making gravy, I just use the drippings from the turkey, sometimes I throw the neck in for a little extra, if I need to make some more.  Call me squimish, but I usually toss the rest, but that's just me.