I ordered the clips from Nikon and replaced them myself. Can't remember the exact price, but they weren't terribly expensive. Thinking back, it was kind of funny how the phone tech had the numbers very soon after I asked for the part (as if they were very familiar with the part number of that item).
I fix things for a living so the repair wasn't a big deal, but I did have to take the grip pretty much completely apart. If you can't find a suitable substitute, I'll gladly fix it for you if you buy the clips.