I will need more context. Please email mgpickerstudio@gmail.com for more prompt feedback.
I don't know why would you need to know the menu item id. I guess it is because you need to update the menu label based on some states that will be changed in the menu command.
Currently, we don't provide API to query the currently triggered menu items. We can provide this feature if really needed.
Otherwise, you might have to hardcode the menu item id. Something like commandButton16.rightmenu[1]