If you need to paint it and simply can't find a replacement plate I'd try "grill" paint. Grill paint is a high temp very durable paint used on Barbecue grills that has a finish similar to gun "blue." The reason I'd use this is because it's thin and wouldn't be so thick like normal paint to alter the clearance for the film. I used to rebuild / restore military type firearms and grill paint is a little known secret for and amazing finish that looks anodized yet it's just a spray can.