See if a magnet sticks to it.
That is not always a good test. A magnet sticks to the "stainless" grates on the Summit.
This is correct. "Stainless" steel is still ferrous so sometimes magnets can stick depending on the alloy and magnet.
However, if it does stick. The results could be flawed. If it doesn’t. The results are definitive.
Exactly what I thought. My guess is you have done the magnet test and it stuck. My other guess is that you have a normal gbs grate.