Not sure if they all are, if you find one it may be "short chambered" and will also need the expense of a smith with a pull through reamer. There is a "work around" on this that is very safe & doable if you reload (factory length brass wont chamber fully), you will need to trim your brass back a bit, In my case it was 12 thou or so...basically you are "wildcatting" your brass to fit the chamber as delivered. It works and is safe in the gun you shorten them for but will have a bit of headspace in a factory chambered rifle.
The "Tradex" barrel I installed on my '42 Underwood indexed perfectly for gas valve/slide line-up so that made installation very easy. Another point i will make to a do-it-yourselfer is head the advise that you will need a poppet nut remover tool to safely remove the gas valve poppet with out damaging it. I made my own tool (piece of drill rod, drill & bits and a hacksaw all that is needed, harden & temper the tool after its built) but i think they can be purchased.