Did you notice the amount of rust on all of the threads when you removed these from your water pump?
Any type hardware that is near the engine coolant will have this issue. The hardware is pretty small diameter too, so don’t mess around with ancient, rusty hardware. This kit includes: 3 studs. 3 nuts, 5 double washered bolts and the LOOOOONG 12mm headed bolt (goes through the center of the water pump, through the timing cover and into the block).