JPA I had the same problem sourcing my hat channel. There was no writing anywhere and I was only clued in after I noticed that it was not hemmed. After much back and forth I finally had a new batch delivered and I noticed immediately that the old stuff weighed like twice as much. It was not even close. There was also an obvious difference in the flex.
Anyways the point of my post is that my new hat channel has the number stamped on it and it matches up perfectly with the number in teds spec sheet for the hat channel.
So I would order it by giving them the spec numbers and tell them you want it stamped right on there so you can confirm and finally put this to bed.
Had I known it was going to be an issue, I would have done exactly that. Unfortunately, at this point I would have to order about twice as much as I would need in order to get it made. That's what my local supplier finally broke down and suggested.
I ended up weighing a stack of it, and sure enough, 20 twelve foot sticks of the "correct" channel comes in at one or two pounds less than the spec sheet says (I chalked that up to my scales) while the other stuff was just under twice that. So there's no question about the difference.
And Fred, that's exactly how I felt. A geographical oddity