Here's a link to the manufacturer's website with an e-mail address.
http://www.warrencutlery.com/mcart/i...els+%26+Gouges
The tools has a ferrule, so I imagine as long as you don't beat away at the tool, you should be able to use a mallet. But check with them to be sure.
Reshaping can be done with emery paper if you have the time--start with a coarse sheet and work your way to 400 grit--800 if you want a polished finish, then strop and you're done. I usually end up rounding off the corners once in a while by mistake. So, it isn't that hard to do. If you buy a cheap chisel at the local Walmart, Target, or use an old beater chisel--even a paint scraper--around the shop, you haven't lost anything, just gained the experience of customizing your own gouge. Besides, it's fun!
Bob L