Cast Iron steering knuckles

[KidWgn]

Is there some sort of definitive guide as to which years/submodels came with cast iron knuckles? What are the alternatives; steel, aluminum?

Looking at a DJM 2/3 drop kit for my new to me 2012 LTZ, and am noticing that it states that it is designed only for vehicles with cast iron knuckles.

Tried searching around, but I didn't find anything useful.

Bonus: Anyone running a DJM kit and wish they had gone a different direction?

 

[swathdiver]

Yours should be cast iron but to be sure, get your magnet out.

 

[Joseph Garcia]

Yep, get your magnet out, and if you get a STRONG attraction, you will know.

 

[Caddylack]

I've also been wondering about aluminum vs iron knuckle, as Rock Auto has listings for both.