I imagine there must be at least one company in China selling brass covers with Fender dimensions. Have you looked into Japanese tele pickups? JV Fender & Squier, Tokai, Fernandes etc. Sometimes we see them for sale at the usual places. I have a Breezysound. Just tried but failed to find the original pickups and measure the cover for you. I will look again. The neck was really muddy so could be brass inside.