electrical floor pockets

I'm looking to replace our floor pockets -- the lighting connectors inside need to be replaced and I'm doubtful the lid will survive removal of the flange, there's so much black floor paint and varnish in the screws. Lid looks to be cast aluminum with textured top surface and logo/brand in...

A large, late 1950s civic theater is embarking on a maintenance program. Some of that requires the replacement or refurbishment of stage floor pocket covers and i wonder if anyone has a source (or contact) with someone who does. Sought, are pocket covers in good condition like the one pictured...