Yes, QuickBooks Desktop (QBDT) Enterprise Silver plan doesn't manage bills of materials, @AFI. Let me share further details about it.
The Silver plan only has the basic functionalities. The bills of material feature is only available with QBDT Enterprise Platinum and Diamond plans. If you want to continue using this feature, you'll want upgrade your subscription or go back with QuickBooks Enterprise Platinum.
You can check out these articles for guidance in upgrading and available plans and feature in QuickBooks Enterpri
Once upgraded your subscription and ready to set up a product you manufacture using components in your inventory and track bills of materials, you can visit this article for details: Set up your product’s bill of materials.
Keep me posted if you have clarification about bills or materials and other features in QuickBooks. I'm always happy to help.