[Arran]

From what I remember from working on several transformerless Philco sets some have that choke on a proper cardboard form slipped over the body of the capacitor, but others have a length of 22 gauge wire wrapped around the outside of the capacitor shell itself. If Mike's calculation is correct, and likely is, then the purpose of the choke must have been to block power line noise from interfering with the IF frequency of the radio. Whether this was ever needed at the time, let alone now, is debatable since AC/DC sets produced by most other manufacturers chose to omit using a choke in this position.
Other then converting a true hot chassis set to one where the chassis "floats" electrically, I'm not sure that there are many mods one could make to make an AC/DC set safer short of operating the set through an isolation transformer. The end user is unlikely to ever come into contact with the chassis inside one of these sets anyhow, the original manufacturers usually issued these sets with cardboard or plastic backs, with push on plastic knobs, in some cases they even concealed the screws holding the chassis in place in one way or another. Realistically these sets are pretty much a novelty to anyone other then an antique radio enthusiast, and might be plugged in and played only occasionally, if at all. Even with my own collection there are one or two sets that I use semi regularly, the rest sit on a shelf and collect dust, i should really put them into rotation more.
Regards
Arrran