Just try and find a vendor that stocks both, and see if you can't get them to supply a close match.
Plastics of different compositions take pigment in different ways. The same shade applied to two different plastics can often lead to a discernible colour difference between them.
Maybe you can do the coffee trick to darken one that is lighter than the others. Some people do it to age white pickup covers. Doesn't take long but might be hard to get a perfect match.