Change a specific field to read only after update

Change a specific field to read only after update so they can only update that field once.

So I found the following from the knowledge base but it does not work even after I change the $form_id number to match my form.  And I do not know how to target specific fields on the forms... but either way this hook is not changing any of the fields into read only anyway after one update

add_filter('frm_user_can_edit', 'check_user_edit_entry', 10, 2);
function check_user_edit_entry($edit, $args){
$form_id = is_numeric($args['form']) ? $args['form'] : $args['form']->id;
if ( $form_id == 5 ){ //change 5 to the ID of your form
if ( is_numeric( $args['entry'] ) ) {
$entry = FrmEntry::getOne( $entry );
} else {
$entry = $args['entry'];
}
if ( ! current_user_can('administrator') && $entry->created_at != $entry->updated_at ) {
$edit = false;
}
}
return $edit;
}