Hi Justin,
Gosh, some of us predicted this might happen.
Brownells sure didn't expect so many orders for that item. I do have one of their 1/16" brass punches and also a regular steel one from the hardware store. I don't particularly like the idea of using the steel one on a Rohrbaugh, but I bet it will be done quite a bit by some owners with no real harm done to the pistol.
But, I think if I didn't have the brass punch and couldn't get one within a reasonable length of time what I'd do is fabricate an old fashioned dowel plate, and make a usable punch from a good straight-grained piece of hardwood. A dowel plate is just a piece of steel, about 1/4" or 3/8" thick, with different sized holes drilled all the way through it.
The idea is that you whittle or split a piece of hardwood down until it is close to the size of the largest hole in the dowel plate, and then drive that piece of wood through successivelu smaller holes with a mallet until you have just the diameter you need. I used to make dowels for my uncle's cabinet shop that way when I was a kid. It's a more work than going to the store and buying doweling ready made, but by doing it that way you can make any size or type of wood dowel you want.
A good straight-grained piece of hardwood with the right diameter would be just fine for driving out the disassembly pin in the Rohrbaugh for quite a few disassemblies before you'd need to make another, and it would be even gentler on the pin than a brass punch.