I've looked at those too,they do look like found parts,but making them out of some aluminum rod would be pretty easy,even with just a dremel and a grinding wheel possibly. (A lathe would be ideal)
I'd say they look like aluminum, judging from the darker color of the steel rod going into them. So that would make them easier to make aswell. I'll still check around and see if they match a found part if possible to find them.