and what if you don't know for some reason when a piece of music has been created? Let's say that you don't know about All Night Vigil (an incredible masterpiece in my opinion), and someone would say to you that it was a revolutionary work created in the 15th century, will it change your consideration of it?
Yes! Or would pianists and conductors sniff at e.g. Rachmaninov's Third Piano Concerto
and refuse to perform it, if they were approached by a young 21st-century Rachmaninov
In fact, there have been parallel experiments about this in literature, where literary agents and publishers are sent type-written copies of things like Great Expectations
or Crime and Punishment
or The Sound and the Fury
or even Jane Austen's
novels, and they are not only roundly rejected, the trick is rarely recognized!