Pot metal. Not easily welded at home. I know they sell rod that is supposed to work with a torch but I've had no luck with it. I'm a pretty good welder but I'd pass on any cracked or broken pot metal. If you found someone who could repair it, it would probably be cheaper to find a better pair. IMHO
so what is pot metal? Because the metal looks like it is rusted, chrome is bubbling up and stuff. but there is no "rust" color anywhere.
Pot metal gets pits, it really does not get rusty. All the bubbling you see is the pot metal pitting. I think its a zinc alloy.
You can tie up some money in the parking lights if you are are going for show quality. They are very prone to pitting and are expensive to replate. The fewer the pits the less it will cost to replate. Fixing the pits is labor intensive and costly. I have a set with light pitting that need plating for show. If you are interested...PM me. I'll get some pictures.
Mine were pitted and my friend and I ground off the pits and I had them chromed.Cost about as much as my bumpers!