My new headers came in today!
They came from Pro Auto Luxury on ebay. Here is what I got (minus the passenger side header):
Nice thick flange, measured at 0.370" with my caliper:
Here is some of the welds, some still had the discoloration in the HAZ:
The ad for these on ebay said they are made from 304 stainless. I think that it might be 409 stainless. 409 is magnetic and 304 is not. The flange may be regular carbon steel since it appears to have a clear coat of some kind on it. You can see what looks like a run in the coating from the flange down part of the tube in that last picture. The coating looks like it is only on the flange except for a few runs on some of the tubes. I will know for sure once I get the motor running and have some heat on them...
Overall, I am pleased with them at this time.