Need key blank for Sears Tower safe

Hi Ken, I was given a Sears and Roebuck Tower safe that my dad purchased well before I was born. It is a great safe and the perfect size for us. Problem: It has a key, but only one. I don't like the idea of only having one key to anything. I have asked a few locksmiths and have searched the internet to no avail. I am trying to find 3 or 4 keyblanks that I can take to a local locksmith to make us more copies of the key. The safe is s Tower safe by Sears and Roebuck. Type C, class 1HR. It is a Yale and Towne key FP3. The key is unusual... very light... aluminum maybe? I am going to take the safe to see if a newer locking mechanism can be put in, but if it cannot, I need to find at least 1 (but prefer 3 or 4) keyblanks. Any help would be appreciated. Thanks!