I know 3D printing but my son is an expert at it. Google Evan Kuester for his work. He works for 3D Systems, a company that builds 3D printers capable of printing in virtually any material. Asteroid dust is one of the more exotic materials for space travel. But you can also print in more common materials such as a variety of plastics and very durable nylon. They work with Formula 1 racing to build a variety of disposable car parts, so these vents are easy, and job shops can provide the printing services for you if an accurate electronic model is available. Such a model can be built by starting with a 3D scan of a good original part. The scan can be enhanced electronically if its not completely straight or damaged from age. Even the movable fins could remain movable, all printed in one shot, or separate pieces. The cost per piece is still quite high regardless of who does the printing, but these cars are very valuable now, so cost may not be in issue for some of you. Attached is an image of a prosthetic arm designed, modeled and printed by my son, it made him famous in the industry. You may be amazed by what these printers can do when printable models are available. I can ask him what he needs to build a model for you. Maybe they will work with you, or provide you with sources.