The GM part number is 25504235 and GM Parts East shows it as available. It is item 22 in the exploded diagram and parts list at the website below.
http://www.gmpartseast.com/buick/com...9mw94gj47.html.
I searched that part number and had various results. Discontinued, available at a relatively low cost of $3.84, and available at a relatively high cost of $31.45. You might still be able to find NOS.