Not in a real straightforward way. The easiest I can think of is to
load the popup preview and look for one of the generated links - like
from the *|ARCHIVE|* or *|UNSUB|* tags, and then copy the XXX part of
the &id=XXX parameter in them.
I'd guess that if you have a need for that for some reason, you
probably should instead be designing a template in the web ui and then
using that when creating your campaigns.
jesse