That is correct. The MFG-STK transaction is what moves quantity and cost from WIP to inventory.
A POTF part number does not exist in the Part table… so it by definition cannot be received to stock. If you created the part number and THEN received it stock, you’d mess up all KINDS of costing because then you’d have to SHIP from stock to a sales order that’s expecting a shipment from WIP. @hackaphreaka is correct, this is not the problem that needs solving.