The Italian bbl tools are scrapers, nothing fancy.
They may well have been shop made from broken or otherwise used machine tooling.
They do alot of things like that 'in house'.
With a bit of practice, you can remove a little or a lot of material while keeping an absolute ripple free surface on the tubes, which is a trademark of the high grade double gun.
Don't let the coarse teeth fool you, they can cut a very fine finished surface.
The one standing up in the pic is for the under rib on a SxS or perhaps the side rib(s) on an O/U. The slight convex shape easily shaves the rib shape clean and level.
They use very little draw filing to polish, as it doesn't elliminate waves and ripples,,you need something to bridge distances to elliminate it. Draw filing works, but it does put ripples into the surface.
Plus the scapers, sharpened with a mirror finish on the final cut tools, will leave a surface that requires very little final polish with abrasives. The less the better to avoid putting any ripples back into the surface.
Single point V shaped hand scrapers are used around the top & bottom rib joint, forend lug & short rib.
They can also be used to lightly scrape the bbl area adjacent to the top rib as well as the side of the top rib.
I use this type for cleaning the solder from re-rib jobs on doubles and other such jobs.
Lacking a set of nice Italian made scrapers like the pics show, I use coarse cut files length wise. A couple that I have just slightly relieved the ends so they don't gouge the surface & the middle portion cuts. You can actually flex them a tiny bit in using them too if you use thin enough files.
The coarse teeth do not load up & scar the surface and clean easily when needed. Gentle pressure allows a nice smooth cut & leveling the surface is quite easy.
Mounting a wooden block handle like the tools posted is a great idea. I may do that next time around.
...but I'm getting kind of tired of dbl bbl polishing though!