Sent the dropside latches and hardware for powdercoating. The plastic handles had to go as they were cracked and covering some surface rust (and in any case would have melted in the kiln). Replacement handles were fabricated out of aluminium stock which was then rivetted in place and covered with a black latex dip.
Rebuilt handle after 2 coats of latex dip:
First Step: two of the latches; one with plastic handle removed to expose the rust: