Early A-5's also had the "suicide safety", and the immediate post-WWII guns had it in front of the trigger guard.
The point I'm making with A-5's, however (as well as Double Autos) is that even some single barrel guns shouldn't be used with steel. True, there's far less risk with current steel than with the early stuff. But if you have a "collectible" gun on which you don't wish to ring bulge the barrel, it's best to avoid steel. The Miroku-made barrels will interchange, and that's a solution in the case of A-5's.
If one wants humpback barrel recoiler with steel receiver Yamato or Yamamoto branded one is great choice (some were branded Herter's though those do not have magazine cutoff switch). One in very good shape can be had for <$400.
