You are able to update products from MMA Silver Star with Stock Sync. Just choose on MMA Silver Star template after choosing to update existing products in your store.
1. Go to Setup New Feed > Choose Update existing products.
2. Choose or search for MMA Silver - All Active items template.
3. Once created the template it will direct to feed details page because there is no any file setting need to fill up.
4. If you would like to do any changes in the field mapping section, then you can click Edit settings and go to second step.
5. If there is no any changes, you can proceed with the Start Process to import the products.