i think you can make use of the assembly variants feature without deleting parts
The assembly variants option is great for such task.
You can do it manually too.
In Layout, select the ECO toolbar (you can set the ECO file to a dummy path; you won't use it).
Delete your parts (the copper will stay because this isn't part of the automatic ECO process).
Set the view options to not show unrouted nets (hide the ratsnest)
Generate your assembly drawings
Close without saving!
If you only do this occasionally this process isn't too tedious. If you do this a lot then the variant option is worth the money.