Hello,
This BAPI can be used to create a sales order with his items. Same than you can do in VA01.
The BOM will be exploded or not depending on the configuration and master data. I don't think the explosion of the BOM depends on how the sales order is created.
Read this article that explains how you can control the BOM explosion thru the Item Category and Order type.
What Is BOM Referring to SAP SD
Thanks and Regards,
Mariano