I just had the same problem and had to replace kickstart pawl stop plate.
I found putting the rivet back in to be tricky, especially if you don't have access to rivet gun. Not much room for a bucking block. I ended up making a little assembly that secured the rivet head in place and could be set on the anvil of my vise.
View attachment 17680
Also, I recommend putting a thin layer of metal beneath the pawl plate to raise it up a tad. There is not much depth of contact between the pawl and the plate. That becomes even less if you add shims to reduce lay shaft end play.