Cobalt steel is not as tough as carbide but there are carbide drills for metal but they are expensive and for a one shot it is nice to know a masonary bit works in a pinch.cobalt drill bit? should work better then a masonry bit I would think.
I was doing some research. I suspect this part # may work without any drilling. This is just from eyeballing up the pictures though.
42-06-0310
https://www.ebay.com/itm/NEW-GENUIN...0310-2450-21-2451-20-42-06-0301-/182350057329