Well you would never get the source code, but you see of course the script(s). I am not in the beta as well and that really sucks. I would like to test SS3 for free. Btw with the exeception of TF 2 Beta you can try everything as normal user as well, just use:
TF 2 Beta might be needed for some systems until the normal one gets all fixes. SS3 you can play without beta as well but you have to pay.