Hmm.. I can't see my screenshot - it is telling me that I need to login to view it, even though I am already logged in.
It's there. I see it. It sometimes takes longer for the image to appear even though we can open and see the text.
It sounds like you mainly need to make one small change:
Don't link your table of lenses by the manufacturer's ID number for the lens. Use an auto-entered serial number field for that purpose. Now you can create a record for your pre-orders and it can be correctly linked where needed. When you receive the lens, you then update your record and record the manufacturer's ID in a separate field in the lenses table.
And you'll be able to easily find all such records by performing a find for Lenses records where the Manufacturer's ID number field is empty.