Yes, it's a high quality metal cutting hole saw, they are available thru McMaster-Carr under hole saws. They cut a very round hole. Unibits are also very handy for opening up holes, but when a Unibit is used to open up two misaligned holes you remove material from both surfaces. With a Rotobroach you will only remove material from the aft surface. Either approach works, it doesn't really matter which method or tool is used, you just want to get the job done in the most efficient manner available to you.
Unlike most of the members here, I didn't have to go out and buy a bunch of expensive special tooling to work on my Airstream as I already had them for my day to day pay the mortgage job.
I recently did this using a reciprocating saw with metal blade and then grinder to finish up. Just make sure you modify the rear of each notch. Also a good idea to pick a constant point somewhere and check the finished job for squareness and alignment.