Say hello to heaven, Chris Cornell!!
Here's mine - I took a chance on this from an Amazon.com reseller a few years ago. It was listed under 'collectible' for the album listing. I asked about it on here years ago and never got a response. It looks like it might be legit, but I can't say for sure.
Edit - I know the picture is a little blurry so it may be inconclusive to tell. I just uploaded the original one I submitted. I had a crappy phone at the time and haven't taken a recent picture of this. I just did a quick search and found it.
I don't remember it myself but i have seen a few sellers on ebay recently state that they got their signed copies of this from a Newbury Comics preorder for an autograped version of "carry on". And generally newbury does this by including an extra signed booklet. So based on that yours seems like it could be legit. But again i never personally saw them do the booklets for "Carry On" like i am certain they did for "Scream". I also checked the "waybackmachine" for old versions of their website around when this came out and found no reference of it. But if in fact they did do a preorder there is a decent chance yours is real.
Geoff, I order that autograph CD from Newbury comics as well! And like mcnish mentioned, I got an extra CD booklet as well. Funny thing is, the extra booklet was autographed by Yogi (I assume this person to be Yogi Lonich who has worked with Chris Cornell). I tried looking for an old post about this pre-order, but the best I could find was a link with a metnion about it on a Pear Jam forum (here's the link, but of course it doesn't work hahahaha http://community.pearljam.com/discussion/50876/chris-cornell-autogr... )
And for clarification, the Carry On booklet was signed in the exact same area as the one you purchased. Here are a few pics of mine!
No problem! Glad I could be of help!