If $id were 60201 would you really only want to print it to OUTPUT_A?
If so, you could put @a in a hash (as you mention) and then test the key like so:

my %a = (
        60622 => 1,
        60516 => 1,
        60201 => 1,
    );

...

if ($a{$id})
{
  print OUTPUT_A  "$fn, $ln and $id";
}
elsif ...
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