Pivot Shoe

Hello. I'm looking for pivot shoes for this pictured coil balance. I'm not sure if 15-177 is the right one. The cut out on the bottom of the coil is slit out. It looks like it catches in the groove of the pivot shoe. The description didn't assure me if I picked the correct shoe. Please review the pics and dimensions and verify if 15-177 is correct or if there is a different one. The back of the shoe does appear to have a blue slate Thank you.