Header Wrap By Starter

I`ve posted this before, I bought a used set of wrapped ,TTI`2" headrs from a guy in witchta, I rewrapped them w/ intentions of having them hi heat coated afterwards, Wanted to make sure they fit right, and that's been about 8 yrs ago, they haven't shown any rust problems yet.
I wonder if TTI uses a higher quality material then some others do?