I haven't seen an NOS grille on ebay for quite awhile. They show up from time to time, usually years apart. I don't know of anyone that has one either. Your best bet is to find a decent used one, and have it rechromed. I can check to see what I have left for used grilles, I'd be willing to donate it to the cause. I've kept a few unbroken, minimal-pit examples. I also know a heck of a chrome guy and could ask him the cost.
Mark