Bruce's reply was factually helpful, although there was no extra set of mounting screws in the packaging, like there was no reverb pan.
It seemed sensible to try the amp out before making any attempt to bend the chassis back, to find out it if was working at this stage. What happened when I did? - see part 71.
From: Zinky Electronics
Subject: Re: Superfly is damaged
Date: Wed, 10 Feb 2010 18:16:25 -0700
Yes, it is safe to operate.
However- I would absolutely use blocks to apply pressure on the chassis to bend it as close to square as you can get it.
Should be an extra set of mounting screws in there. If not, the screws are size 6-32, 3 1/2 inches in length.