I'm not sure the average person or movie fan realizes how "fluid" movie production is. How costumes and props are not what you think they are or not the same for the entire film. I have been involved in hundreds of films and TV shows over the past 35 years and it often comes down to what works on the day. (or for that shot) So the idea of contesting what is more or less accurate is a bit of a impossible thing to achieve. The number of times a costume or prop has been radically altered or quickly fixed after it get's damaged on set, is common. Also, "story line" or "plot" damage or aging on a costume is often meticulously documented with daily photos or in some cases scene by scene reference photos, taken by the wardrobe department. So what the piece looks like in one scene may be not the same in another. Some of these changes are obvious, while others are left to interpretation of the viewer or end up on the cutting room floor. Then there are the "photo shoots" either for a magazine or publicity. These are often done without the original film crew or in some cases not the original costume or prop. So using these as reference is not always a sure thing. (We rent things all the time to photographers who are shooting promo stuff for a movie, even though we didn't work on the film)
In addition, there have been many times when we have made something for a film, and when I see it in the finished movie in the theater, I am surprise how different it (prop or costume) looks than it looked at our shop.
Over my career, I have worked at the 3 largest prop houses in Hollywood and worked for the largest costume shop in Hollywood, I have seen hundreds of famous costumes and props, and many times they are complete pieces of crap. But on screen, they looked great. It was very disappointing to see some of my childhood favorites and realize they were completely fake or just a piece of painted wood.
When I first started making movie props (1981) at "The Hand Prop Room", (Big LA prop house) I was told, "paint it black, the camera will never see it". Well that was the general advice, basically make the prop out of anything because the camera will only pick up so much. Well one day, Jim Cameron (a director I believe...) chewed out my boss for these really crappy looking props that the shop had made for his low budget movie called something like "The Terminator". This director had no idea what our budget had been or the amount of time we had to make these P.O.S. props for his low budget Sci-Fi film. But, I realized something that day, it doesn't make any difference what the camera "can see", because the camera doesn't sign the checks. So from that day forward I always tried to make whatever I did, look great while it was in your hand and never counted on the camera to not see the hot-glue drips or giant seam running down the back of that rubber gun.
So be careful what you ask for, you may pay hundreds of dollars for a "piece of crap", but it will be screen accurate.... .