I seasoned my kettle and I keep it a little seasoned, just wiping the inside from time to time and taking a brass brush to the lid interior and grates as needed. I have no problem with rust. I do not have cast iron grates, but, I keep a cast iron skillet in the kettle from late March through November with no rust issues.
I'm feeling bearish, and I'm packing a Wusthof Grand Brisket slicer from MABA
"perhaps...but then again...maybe not..."