I believe you could poke a pencil through most of the hull of the ISS as it is; a stanley knife anyway. Short form, weight is critical, so they don't use "hull armour" to protect - it's things called "Whipple shields", which are pretty much spaced armour, except it's spaced tinfoil. The micrometeors vaporise away from the main hull, and I assume it could be easily replaced by more tinfoil.
Pressure sealing also comes from liners & layers, typically special non-flammable plastics I believe. And radiation shielding will probably come from major structural elements - like the "core can" in the illustration. One end will have a "rac cellar" built in. Right behind the batteries would be good, particularly if you can point that end at the Sun.
So there's nothing in orbit which can withstand machine gun fire, basically, let alone a baseball at escape velocities.
Given that, and given more actual structure than shown there (eg. multiple redundant layers), I'm quite comfortable with the theoretical use of inflatables. Would I want to be the first person to stay in one long-term? Ummm ... but I'd give it a go for the chance to be in orbit ;)