It does look like resin finish , should be fine to fix with epoxy .
Non structural easy bog fixes .
If you dont have resin id suggest Araldyte or Selleys for porcelain fixes . Its cheap and easy , is thick , ( like toothpaste ) , and white in color , from Bunnings .
Chip off loose bits sand area with 400 grit.
Make a flexible squeegee that u can wrap around the rail profile . ( soft plastic ice-cream lid ).
Pile resin oversive on hole .
Scrape the curved squeegee over the area and it will be almost perfect .