Jager Regiment 58 Grenade Pin or Tinnie - WWII German FJR

Very cool pin or tinnie in the shape of a potato masher grenade. Gold finish looks like an applied foil with J.R. 58 etched. I could not find an army 58 Jager Regiment so I do believe this is referring to the paratrooper regiment (FJR) 58. Whatever the unit, it is a cool pin that I have not seen before.