Mario, a while back I purchased an assortment of car parts on the auction site. Probably what was available in the 50’s when kits were popular. I’ve got some that are close. I’m guessing they are brass. But they don’t appear to be soft castings. I’ve used only the straight ones building some wooden cars. They have holes you can insert some small pins to give some extra support.
Shown with an Atlas X29. The shape is pretty close. No lefts or rights. You just flip them over. If you want to try 0ne , Two or even Four. Hit my e mail and I’ll get them to you.