I don't know what chemicals were available in that time period. Maybe John Z can remember, but the stuff left over on my original is what RTV silicone would dry like, but it wasn't shiny and looks like rubber. Someone from the day might be able to come up with what would have dried to be like and what could be substituted. If the silicone wouldn't be so shiny, it would work. It almost looks like the non-hardening gasket maker, but again isn't that shiny.