Haven't had these off, but was wondering if they are powdercoated stainless or what. Looking to remove the silent choice and extend the risers by welding on 6" extensions to run a different cam.

You would be better off to look for a set of used full length risers than to weld on those.
Then sell yours a complete silent choice set up.

see if a magnet sticks to them,,if they do their steel if they dont then their stainless.

The only way they came was S/S, they cane be welded but the suggestion above is a good one.

Phil

Already tried that and didn't stick.