It's also worth noting that Hot Toys is most likely working from renders of the design itself, and not the final film.
So, just like the Mk 46, there is a color difference from the figure and the film version.
Marvel color grade their movies with a strong blue tint. This made the Mk46 red appear to be a bit more almost magenta on screen.
The official Mk85 renders and designs are most likely a stronger gold than what appears on screen after the color grading. I certainly wished the figure shipped with the lighter gold coloring, but I understand why.
I also think Hot Toys color grades their photos to capture the cinematic look of the movies. They probably shouldn't be doing this, if it doesn't accurately reflect the true colors of the product.