depends on the shackle
I have seen them in defender and also at WM and Boaters World. After you get it, tie it in place with a very small piece of SS wire to keep it from coming loose and backing out to become lost in the deep. Also, like you, I didn't want to replace it since the halyard had an eye on the end of it with marlin spikemanship and I was lazy enough to not want to redo the halyard. Finding a replacement pin was my choice, they are out there, check around. I think, I found mine at WM for a couple bucks.