BOM/OPL parts help before PCB fab
I had the same problem.
I found a blog post that deprecated the OPL or CPL parts numbers in favor of the more universal Manufacturer Part Number.

I solved it with the following steps:


From the schematic view click  File > 'Run ULP...'
Select bom.ulp





Export a CSV with all values
Open it in Excel or import it into Google Sheets
Edit it to match the BOM template on SEEED Fusion. This entails deleting most of the columns, as the Seeed BOM format is very simple. 

Note that Seeed only cares about MPN (Manufacturers Part Number) Which might be in a different column on your auto-generated BOM depending on where your library