Lee also makes ingot molds
yes they do.
One tip for using the muffin tins to make lead ingots is set it up on a angle so the lead has a taper on one side. Pliers can easily grip them with no slipping.
It makes they easier to handle when putting them back in your hot-pot. Dropping a ingot in the hot lead can spoil your whole day/week/month..
I mold fishing jigs and lures by the hundreds.