I purchased my new 52 grille about 4 years ago from this place...
http://www.classicautoparts.com/chevy/aboutus.html...it goes by Classic Chevrolet Parts but the address is different. A LOT of vendors these days have "classic" in the name. Personally the above Classic Chevrolet Parts is in Oklahoma and I believe it is "another" spin off of American Classic?
Anyway, I paid 149 including shipping to my door. They run a special on them fairly regular. Mine has held up good in spite of what looks like "dust" in the crevices. My panel stays inside but I do drive it, even on long trips and it does see foul weather. All in all I am pleased with it.