Always wanted one of these too, but haven’t gotten one yet... And electric would be a very nice option to have!
The D45 is the older version of the D455. I don’t know all the differences off hand, but I believe the chimney on the D45 is just an open pipe that you can see right down through, I believe it was changed on the D455 with the added top that yours has to avoid being burnt. I believe the older D45 had a wider/flat burner with no burner slide. And of course older models have metal valves instead of plastic, but not sure when that changeover happened...