function HasProperty(Obj: TObject; Prop: string) : PPropInfo;
begin
  Result := GetPropInfo(Obj.ClassInfo, Prop);
end;

procedure TForm1.Button1Click(Sender: TObject);
var
  p : pointer;
begin
  p := HasProperty(Button1, 'Color');
  if p <> nil then
    SetOrdProp(Button1, p, clRed)
  else
    ShowMessage('Button has no color property');
  p := HasProperty(Label1, 'Color');
  if p <> nil then
    SetOrdProp(Label1, p, clRed)
  else
    ShowMessage('Label has no color property');
  p := HasProperty(Label1.Font, 'Color');
  if p <> nil then
    SetOrdProp(Label1.Font.Color, p, clBlue)
  else
    ShowMessage('Label.Font has no color property');
end;