Some racers had bronze bushings. There are a lot of racers out there in a lot of iterations.
To clarify, the brakes I have are the red plastic sleeve.
I pulled them and cleaned them but just got to thinking about how much of a difference bronze would make. Target bike is a 69 PX10 and that predates the mafac competition brakes, but still, Racers were some of the best brakes anywhere in the 60s.
Also brazed pivots (a la PY10) are not out of the question but I can't find them for the life of me.