Alan,
Don't know bout that bro, mine came out pretty flat, in fact I rolled my past rides the same way too. I don't have any rubbing issues on the set-up I mentioned a few replies ago.
For aggresive offset and suspension set-ups, I'm sure you'll need more than a simple roll on a stock body. In some cases you might need to pull it out slightly too.
It's not the case here as the ThreadStarter's size and offset is quite safe and if he doesnt slam it to the ground, my suggestion will do.
Again, I don't recommend knocking with a hammer because things can turn really sh*tty if the handler is inexperienced . You might even end up plastering and re-painting your rear panel.
Why go through that hassle?
Picture below demonstrates how a rolling kit looks like, and how it's supposed to be done