I looked into this when I needed bumpers for my Nova. I was told the new/triple plated AMD bumpers were as nice as you will get for repro's. I got mine from an ebay vendor Tamrazs. They have free shipping, and sell AMD's......For what they cost, they're nice. The fit is real good, and they look like the originals. The chrome is good, but not like you will get from a high dollar chrome shop.
If your originals are in pretty good shape, I'd send the to Tri City Plating in Tenn. They did the bumpers on my 68 Chevelle, and my 69 ElCamino. They are very nice, and they give a life time guarantee. Their cost is about $350 per bumper. The AMD bumpers were about $140 each.
You can see the front bumper below in my sig pics.