No, but a single toolbar button (and a command) can be used by many different applications and business objects. Toolbar buttons are reused (or shared) by applications, which is much the same thing.
Take the command "new" for example:
This way your users get used to using the single "New" button.... and it means "Make a new one of the thing I am currently working with".
Also see:
Does VLF-ONE have a main form menu bar?
Do VLF-ONE and VLF-WIN handle the main form tool bar the same way?