I bought an Ultra Aluminus case. I have an anodizing setup in storage. The inside is full of unfinished bare aluminum that personally, needs a bit of finishing IMO. However, it is riveted in place.

When building a kit car, like our Factory Five '35 Hot Rod Truck, one of the most time-consuming single processes is the sheet metal work. It's not hard, but there's a lot of holes to drill and rivet!