Hi JD,
From my understanding, Installation Warehouse seems to be a good name instead of Finished Goods warehouse, which is more semantically correct in your case.
When making Delivery Note, the Sign Board will be removed from Installation Warehouse and marked as delivered.
However, you should make a Sales BOM Item, say Sign Board Package, that will be a package containing Sign Board and other items required for installing Sign Board, so that the inventory of these get tracked, but that of Sales BOM Item will not be tracked.
Using Sign Board Package in Sales Order, Delivery Note and Invoice will affect the inventories of Sign Board + relevant other material.
Hope this helps.
Thanks,
Anand Doshi.