No. The back terminal cover is not available as a spare item, however depending on quantity required, they may be able to be
procured as a special.
That being said. If they are looking for a back terminal, they can buy the 435A as this comes with the back terminal.
For further information, please visit https://www.clipsal.com/Trade/Products/ProductDetail?CatNo=435A&c=1&ms=1&mg=336&g=3362354