Rear near side light part number - Coachman Amara 480 /4 2000

Hi could anyone help me please, I need a new rear light on my Coachman Amara 480 /4 made in the year 2000. I have seen one that looks the same but the dimension is slightly out on one measurement.

Just don't want to run the risk of buying the wrong one then I have to send it back. Can't find any other site that can help me on the part number.

If you look close you can see a triangle reflector. The pic on the website looks like it's for the wrong side but if you look close the triangle is upside down? So this looks correct but am just not sure?

Hope someone can help.

AMAZON - Hella 2VA 007 502-011 Combination Rearlight