I have an RD jack receiver plate. There appears to be a top and bottom as one of the flanges/curved areas that wraps around the long is a bit longer than the other and the flanges around where the jack receiver tube goes are not the same all of the way around, with one flange longer and one shorter on the top/bottom. So, how does one know which way it's supposed to go (the originals on my car were completely disintegrated)?

Water drain hole is on the bottom.

The RD unit doesn't come with a hole. I was going to drill the hole when I realized that the plate is not symmetrical.

For anyone who searches this, I contacted RD and after some investigation the long flange at the rocker goes on the top.