Bwana Bob, I approach this from a different angle (how strange that is, for me ......)! If these sights are still avalable from Rigby and https://mclaughlincustomfirearms.com/rigby-peep-sights/original/, I can't see there being any issues. If these sights were really causing damage to the person firing them, they would have died a natural death, years ago. It is best to be cautious but .......
Hope that helps
D'oh! Homer
-------------------- "Beware the Lolly Pop of Mediocrity,
Lick it Once and You Will Suck Forever"