The Reader Extensions function in Acrobat Professional does not include enabling an interactive PDF form for the PaperFormsBarcode object.
The barcode turns grey in Reader because the form does not have the barcode right. On the other hand, any version of Acrobat provides barcode encoding. If you want to distribute a barcoded form for Reader clients, you must use LiveCycle Reader Extensions ES2 to apply a barcode right.
Steve