St. Charles Isuzu has always been able to get my OEM parts, they ship for free, and the price is 10 or 15% below list price. Other dealerships vary in the price they'll quote you.

Also, I'd be surprised if they couldn't sell you just the tabs, or maybe a kit of some sort. Make sure you talk to Merlin if you don't like the answer you get elsewhere (even from another parts counter tech at St. Charles). In my experience he has always come through even when others told me a part was unavailable.