Chances are it is P&O Steel, which is not the same as cold rolled. Cold rolled general stops at .125" Thickness, sometimes 10ga or .134" thickness. It can be found in thicker, but is special order.
P&O is hot rolled steel that goes through an acid bath to clean mill scale, than is oiled. (Pickled & Oiled) It has a much cleaner surface, but is not the same as cold rolled.
Cold rolled is general stronger because it is cold worked, and than annealed to increase its ductility.
Im not sure why anyone would use hot rolled for a suspension part, it welds like shit. All my arms are made out of 3/16" P&O steel. It is plenty strong for its purpose and welds up nicely
We have ran cold roll / P&O steel on all our race trucks in the last 10 years and never seen a kit bust. Mostly 3/16 thickness (my Toyota is 1/4 cold roll but I built that thing super overkill..lol)
3/16 cold roll is plenty for suspension if it is structurally built right. Its all about plating/ gussets and proper geometry. That's what makes a kit. Who cares if its 4130 chromoly plate if its not strong with proper plate work/ geometry.
Its usually the stock mounting spots that the kit is bolted to that rips and cracks apart.