You need on-on, not on-on-on.
The DPTP will allow you to use one side for signal and the other side for ground.
Look carefully - AllParts has black, chrome & gold choices here:http://www.allparts.com/SearchResults.asp?search=dpdt&x=0&y=0
I'm pretty sure this is what I used for my on/off pickup toggles in my poor man's Cowboy.
btw....I'm not a big fan of Radio Shack - only when desperate.... Their quality is not great.