Effect of plate on tune?

[10centNickle]

Do different plate materials affect tune?  Des thickness of a plate affect tune?

[Findecanor]

Yes, the plate material affects the sound profile. Some materials are stiffer than others.
Thicker plates are stiffer and transfer more sound into the case but they are uncommon both for that reason and because they are more involved to make and thus more expensive.
The way the plate is mounted in the case also makes a difference.

There are quite a few plate sound comparison videos on Youtube. Here's one:

[Leslieann]

A whisper in a loud room goes unnoticed but the same whisper in a silent room sounds like a shout.

If you have a noisy board, clicky switches factory lube, you might be able to identify it when listening for it specifically or side by side but is it worth the effort, probably not. On the other hand, if you have a solid aluminum board fully lubed with foam and silent switches, absolutely.