I replaced a target on my Royal Guard before i sold it and shipped it to Liverpool England. I bought the target from Steve Young. I just told him the color target i needed and the name of the game. He sent with a rivet. I hammered the rivet on the target bracket stem and installed on my game.
You will need to remove the playfield from the game and set it up on horses. Go here below to view three short videos i made explaining how i did it. I wish i could had someone video the actual target repair close up, but there wasn't time. Hopefully it helps some with your issue. I have over 25 other videos of some basic instructions on my Royal Guard on my youtube page if you want to view them for further basic knowledge. These days i have a way better HD camera that i use for video taping. I wish i had it when i made the 30+ videos of my Royal Guard.
You might want order a purple and green along with the red and change all three at one time. This way you will have all the correct factory colored targets that belong on the game.
Great player....i miss mine.