This is a high quality reproduction of the Z50 76-79 model outside lower muffler guard.  This one is referred to as “Cover A” by Honda and ours is virtually identical to the OEM version (which is long discontinued from Honda).  This guard is often bent from rocks or running over things like logs, curbs etc.  And if not bent, it’s usually rusty and pitted making it hard to restore.  So, the easy solution is to just replace it with a new one.