Pearson 424 tang bolt

[Brion Toss]

Hi again,
As I understand it, if it has zinc in it, it is brass. So let's eliminate that one. Iron isn't necessarily an obstacle; some of the strongest, most corrosion-proof bronzes contain iron (and other metals that you might think would be a problem), but through the magic of alloying all is well.
It looks like your other choice is a variant on something called "tin bronze", which is actually, you guessed it, a brass, even though it has no zinc. I don't know anything about how it might behave when turned into a bushing ...
Fair leads,
Brion Toss