Related Questions:
Do Items update on an Invoice when the Menu item is changed?
Answer:
Changes made to Menu Items will only apply to Menu Items added to Bookings/Events/Invoices after the change has been made. Menu Items already used will not be affected.
This is the same for archiving or deleting a Menu Item, it'll remain as it was on the Booking/Event/Invoice, but will no longer be available to use in the future.