Hi all. I'm a new member trying to find out if these autographs are authentic. I've been holding onto this for about 15 years. The story about how I came to own it is a long one, but the short version is that it was amongst a lot of records that I bid on during a silent auction many years ago.

Being a Soundgarden fan myself, I feel in my heart they're authentic but have never had it checked out by a professional. I'd like to get it appraised but not sure how to go about doing so. Any suggestions? Thanks in advance!